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Appendicular SKeleton

The Appendicular Skeleton

Fig. 5.8, p. 146

  • 126 bones of the limbs (appendages), the pectoral girdle, and the pelvic girdle

  • Girdles attach the limbs to the axial skeleton

The Shoulder (Pectoral) Girdle-Clavicle (Fig. 5.23(a-b), p.159

  • The collarbone

  • Holds the arm away from the upper thorax and helps prevent shoulder dislocation

  • When the clavicle is broken, the shoulder region caves in medially

  • Attaches medially at the manubrium (at the sternal end) and laterally at the scapula (helping to form the shoulder joint)

  • Shoulder blades

  • Triangular; “wings” because they flare out when we move arms posteriorly

  • Flattened body with 2 important processes:

  • Acromion : enlarged end of the spine of the scapula; connects with the clavicle laterally at the acromioclavicular joint

  • Coracoid process: break-like; points over the top of the shoulder and anchors some of the muscles of the arm

Other Important Markings of the Scapula

Fig. 5.23 (c-d), p.159

  • Suprascapular notch: just medial to coracoid process; nerve passageway

  • Not directly connected to axial skeleton— held in place by trunk muscles

  • 3 borders: superior, medial (vertebral), and lateral (axillary)

  • 3 angles: superior, medial, and inferior

  • Glenoid cavity: in the lateral angle; shallow socket that receives the head of the arm bone.

Shoulder Girdle:

Allows Wide Range of Motion

  • Very light

  • Attaches to axial skeleton at only one point– the sternoclavicular joint

  • Loose attachment of the scapula allows it to slide back and forth against the thorax as muscles move

  • Glenoid cavity is shallow and poorly reinforced by ligaments

  • PROBLEM: easily dislocated

Arm: Humerus (long bone) (I)

Fig. 5.24 (a-b), p.160

  • Proximal end: rounded head that fits into shallow glenoid cavity

  • Anatomical neck: immediately inferior to proximal head; slight constriction

  • Greater & lesser tubercles: anterolateral to head; sites of muscle attachment

  • Separated by the intertubercular sulcus

  • Surgical neck: just distal to tubercles; most frequently fractured area of the humerus

Arm: Humerus (long bone) (II)

Fig.5.24 (a-b), p.160

  • Deltoid tuberosity: roughed area on the midpoint of shaft;l deltoid attaches

  • Radial groove: runs obliquely down posterior of shaft; radial nerve fits here

  • Trochlea: spool-like at the medial-distal end; articulates with bones of the forearm

  • Capitulum: ball-like at the lateral-distal end; articulated with bones of the forearm

  • Coronoid (anterior) & Olecranon (posterior) Fossa: above trochlea: allow processes of the ulna to move freely

  • Flanked by medial & lateral epicondyles

Forearm: Radius (I)

Figure. 5.24(c), p. 160

  • Lateral bone

  • When the palm faces backward, the distal end of the radius becomes medial to the ulna

  • Articulates proximally and distally with the ulna at the radioulnar joints

  • Connected along the length with the ulna with flexible interosseous membrane

  • Styloid process at the distal end

Forearm: Radius (II)

Fig. 5.24(c), p.160

  • Disc-shaped head forms joint with the capitulum of the humerus

  • Radial tuberosity: just below the head; bicep muscle attaches

Forearm: Ulna

Fig. 5.24(c), p.160

  • Medial bone

  • Coronoid process (anterior) & olecranon(posterior): at the proximal end; grip the trochlea of the numerous ina pliers-like grip

  • These two processes are separated by the trochlear notch

Hand

Fig. 5.25, p.161q

  • Eight carpal bones (2 irregular rows of 4 bones each); form the carpus (wrist)

  • Movement among them is restricted by ligaments

  • Metcarpals: palm

  • Numbered 1 to 5 (thumb is 1, pinky is 5)

  • In a fist, the heads become the knuckles

  • Phalanges: fingers

  • 3 bones in each finger (proximal, middle, distal); only 2 in thumb (proximal, distal)

Pelvic Girdle

Fig. 5.26, p.162

  • Formed by 2 coxal bones (a.k.a ossa coxae or the hip bones) and the sacrum

  • The pelvic girdle + the coccyx= the bony pelvis

Basics of the pelvic girdle

  • Bones are large and heavy; securely attached to axial skeleton by the sacral attachment to the lowest lumbar vertebra

  • Thigh bones securely attached to the girdle by deep sockets and reinforced by ligament

  • Most important job: bears weight of upper body

  • Reproductive organs, urinary bladder, and large intestine lie within pelvis

Hip Bones: Fusion of 3 Bones Ilium (Fig. 5.26, p. 162)

  • Ilium: large & flaring; connected posteriorly to the sacrum at the sacroiliac joint

  • Alae: wing-like portion (when you rest your hands on your hips)

  • Iliac crest: upper edge of an ala; important landmark for intermuscular injections

  • Anterior superior iliac spine: anterior end

  • Posterior superior iliac spine: posterior end

  • Small inferior spines below

Hip Bones: Fusion of 3 Bones

Ischium (Fig. 5.26, p. 162)

  • Ischium: forms most inferior part of coxal bone; “sit down bone”

  • Ischial tuberosity: roughened area that receives body weight when sitting

  • Ischial spine: superior to tuberosity; important landmark (narrows outlet through pelvis through which the baby passes)

  • Greater sciatic notch: allows blood vessels and sciatic nerve to pass posteriorly to thigh (buttock injections should be far from this area!!!)

Hip Bones: Fusion of 3 Bones

Pubis (Fig. 5.26, p.162)

  • Pubis: most anterior portion of coxal bone

  • Obturator foramen: allows blood vessels and nerves to pass to the anterior part of thigh

  • A bone of bar from the rami of the pubis anteriorly & ischium posteriorly surrounds this

  • Pubic symphysis: fusion of both pubic bones, forming this cartilaginous joint

Hip Bones: Fusion of 3 Bones

Acetabulum (Fig. 5.26, p.162)

  • Deep socket that is the fusion of the ilium, ischium, and pubis

  • Receives the head of the thigh bone (femur)

Two Pelvic Regions

Fig. 5.26, p. 162

  • False pelvis: superior to true pelvis; medial to flaring ilia

  • True pelvis: inferior to flaring ilia; surrounded by bone

  • For women, the true pelvis MUST be large enough for the baby’s head to pass through

  • The dimensions of the outlet (inferior) and inlet (superior) must be carefully measured

Chracteristics of the FEMALE

pelvis (Fig. 5.26 (c), p.162)

  • Inlet is larger & more circular

  • Shallower, and the bones are lighter and thinner

  • Ilia flare more laterally

  • Sacrum is shorter & less curved

  • Ischial spines are shorter and father apart (creating larger outlet)

  • Pubic arch is more rounded (the pubic arch is greater)

Foot

Fig. 5.28, p.165

  • Two functions: supports body weight and acts as a lever to propel our bodies as we walk or run

  • Tarsus: posterior of foot; 7 tarsal bones

  • 2 largest carry most of the body weight: the calcaneus (heelbone) and talus (lied between the tibia and calcaneus)

  • Metatarsals: sole of the foot; 5 bones

  • Phalanges: toes; 14 bones

  • All toes have 3 bones, except the big toe (2 bones)

Arches of the Foot

Fig. 5.29, p.165

  • Bones are arranged to form 3 arches

  • 2 arches are longitudinal (one medial and one lateral), and 2 arch is transverse

  • The ligaments and tendons in the foot help secure the foot bones, but allow a certain amount of give or springiness

  • Weak arches are referred to as “fallen arches” or “flat feet”

Joints

P.165-173

Joints (Articulations)

  • Sites where 2 or more bones meet

  • Hyoid bone-only unarticulated bone in body

  • Two functions:

  • Hold bones in place

  • Give rigid skeleton mobility

  • Two ways joints are classified:

  • Functionally

  • Structurally

Funtional Classifications of Joints

  • Synarthroses: immovable

  • Mostly restricted to axial skeleton

  • Amphiarthroses: slightly movable

  • Mostly restricted to axial skeleton

  • Diarthroses: freely movable

  • Predominate in the limbs

Structural Classification of Joints

Fig. 5.30, p.168 & Table 5.3, p.169

  • Fibrious: fibrous tissue connects bones

  • Generally immovable (synarthroses)

  • Cartilaginous: cartilage connects bones

  • Generally slightly movable (amphiarthroses)

  • Synovial: joint cavity connects bones

  • Generally freely movable (diarthroses)

Fibrous Joints

  • United by fibrous tissue

  • Eg. Sutures in the skull (Fig. 5.30(a), p.168)

  • Irregular edges interlock and are bound by connective tissue fibers

  • Syndesmoses- fibers connecting bones are longer than in sutures; more “give” to the joint

  • Eg. Joint connecting the distal end of the tibia and fibula

Cartilaginous Joints

  • Bone ends are connected by fibrocartilage

  • Eg. of the slightly movable (amphiarthrotic) joints: pubis symphysis and intervertebral joints (Fif. 5.30 (e-d), p.168)

  • Syndchondroses: immovable cartilaginous joints (synarthrotic)

  • Eg. Epiphyseal plates and joints between first ribs & sternum (Fig. 5.30 (c), p.168)

Synovial Joints

Fig. 5.30 (f-h), p. 168

  • Bones articulate at a joint cavity filled with synovial fluid; eg. Limbs

  • 4 characteristics:

  • Articular (hyaline) cartilage covers bone ends

  • Joint surfaces enclosed by sleeves of fibrous c.t. (articular capsule), lined with a smooth synovial membrane

  • Articular capsule encloses joint vanity, which contains lubricating synovial fluid

  • Fibrous layer of capsule reinforced by ligaments

Bursae & Tendon Sheaths

  • Bags of lubricant closely associated with synovial joints (Fig. 5.32, p. 170)

  • Act like ball bearings to reduce friction

  • Bursae: flattened fibrous sacs lined with synovial membranes and containing a thin film of synovial fluid

  • Common where ligaments, muscles, skin, tendons, or bones rub together

  • Tendon sheaths: an elongated bursa; wrapped around a tendon subject to friction

Homeostatic Imbalance:

Dislocation

  • The bone is forced out of its normal position in the joint cavity

  • Reduction: process of returning the bone to its proper position

  • Should ALWAYS be done by a physician!!!

Homeostatic Imbalance

Bursitis&Sprain

  • Bursitis: “water on the knee”

  • Inflammation of bursae or synovial membranes in the patellar area

  • Sprain: Inflammation (or possible tearing) of the ligaments or tendons

  • Causes swelling

  • Slow to heal because tendons and ligaments are poorly vascularized

Homeostatic Imbalance:

Arthritis

  • Describe over 100 inflammatory or degenerative diseases that affect the joints

  • Most widespread crippling disease in the U>|S

  • All forms start with: pain, stiffness, & swelling of the joints

  • Different types of arthritis have different long-lasting effects

  • Acute forms: bacterial infections; treat with antibiotics

  • Synovial membrane thicken and fluid decreases=increased friction=PAIN

Appendicular SKeleton

The Appendicular Skeleton

Fig. 5.8, p. 146

  • 126 bones of the limbs (appendages), the pectoral girdle, and the pelvic girdle

  • Girdles attach the limbs to the axial skeleton

The Shoulder (Pectoral) Girdle-Clavicle (Fig. 5.23(a-b), p.159

  • The collarbone

  • Holds the arm away from the upper thorax and helps prevent shoulder dislocation

  • When the clavicle is broken, the shoulder region caves in medially

  • Attaches medially at the manubrium (at the sternal end) and laterally at the scapula (helping to form the shoulder joint)

  • Shoulder blades

  • Triangular; “wings” because they flare out when we move arms posteriorly

  • Flattened body with 2 important processes:

  • Acromion : enlarged end of the spine of the scapula; connects with the clavicle laterally at the acromioclavicular joint

  • Coracoid process: break-like; points over the top of the shoulder and anchors some of the muscles of the arm

Other Important Markings of the Scapula

Fig. 5.23 (c-d), p.159

  • Suprascapular notch: just medial to coracoid process; nerve passageway

  • Not directly connected to axial skeleton— held in place by trunk muscles

  • 3 borders: superior, medial (vertebral), and lateral (axillary)

  • 3 angles: superior, medial, and inferior

  • Glenoid cavity: in the lateral angle; shallow socket that receives the head of the arm bone.

Shoulder Girdle:

Allows Wide Range of Motion

  • Very light

  • Attaches to axial skeleton at only one point– the sternoclavicular joint

  • Loose attachment of the scapula allows it to slide back and forth against the thorax as muscles move

  • Glenoid cavity is shallow and poorly reinforced by ligaments

  • PROBLEM: easily dislocated

Arm: Humerus (long bone) (I)

Fig. 5.24 (a-b), p.160

  • Proximal end: rounded head that fits into shallow glenoid cavity

  • Anatomical neck: immediately inferior to proximal head; slight constriction

  • Greater & lesser tubercles: anterolateral to head; sites of muscle attachment

  • Separated by the intertubercular sulcus

  • Surgical neck: just distal to tubercles; most frequently fractured area of the humerus

Arm: Humerus (long bone) (II)

Fig.5.24 (a-b), p.160

  • Deltoid tuberosity: roughed area on the midpoint of shaft;l deltoid attaches

  • Radial groove: runs obliquely down posterior of shaft; radial nerve fits here

  • Trochlea: spool-like at the medial-distal end; articulates with bones of the forearm

  • Capitulum: ball-like at the lateral-distal end; articulated with bones of the forearm

  • Coronoid (anterior) & Olecranon (posterior) Fossa: above trochlea: allow processes of the ulna to move freely

  • Flanked by medial & lateral epicondyles

Forearm: Radius (I)

Figure. 5.24(c), p. 160

  • Lateral bone

  • When the palm faces backward, the distal end of the radius becomes medial to the ulna

  • Articulates proximally and distally with the ulna at the radioulnar joints

  • Connected along the length with the ulna with flexible interosseous membrane

  • Styloid process at the distal end

Forearm: Radius (II)

Fig. 5.24(c), p.160

  • Disc-shaped head forms joint with the capitulum of the humerus

  • Radial tuberosity: just below the head; bicep muscle attaches

Forearm: Ulna

Fig. 5.24(c), p.160

  • Medial bone

  • Coronoid process (anterior) & olecranon(posterior): at the proximal end; grip the trochlea of the numerous ina pliers-like grip

  • These two processes are separated by the trochlear notch

Hand

Fig. 5.25, p.161q

  • Eight carpal bones (2 irregular rows of 4 bones each); form the carpus (wrist)

  • Movement among them is restricted by ligaments

  • Metcarpals: palm

  • Numbered 1 to 5 (thumb is 1, pinky is 5)

  • In a fist, the heads become the knuckles

  • Phalanges: fingers

  • 3 bones in each finger (proximal, middle, distal); only 2 in thumb (proximal, distal)

Pelvic Girdle

Fig. 5.26, p.162

  • Formed by 2 coxal bones (a.k.a ossa coxae or the hip bones) and the sacrum

  • The pelvic girdle + the coccyx= the bony pelvis

Basics of the pelvic girdle

  • Bones are large and heavy; securely attached to axial skeleton by the sacral attachment to the lowest lumbar vertebra

  • Thigh bones securely attached to the girdle by deep sockets and reinforced by ligament

  • Most important job: bears weight of upper body

  • Reproductive organs, urinary bladder, and large intestine lie within pelvis

Hip Bones: Fusion of 3 Bones Ilium (Fig. 5.26, p. 162)

  • Ilium: large & flaring; connected posteriorly to the sacrum at the sacroiliac joint

  • Alae: wing-like portion (when you rest your hands on your hips)

  • Iliac crest: upper edge of an ala; important landmark for intermuscular injections

  • Anterior superior iliac spine: anterior end

  • Posterior superior iliac spine: posterior end

  • Small inferior spines below

Hip Bones: Fusion of 3 Bones

Ischium (Fig. 5.26, p. 162)

  • Ischium: forms most inferior part of coxal bone; “sit down bone”

  • Ischial tuberosity: roughened area that receives body weight when sitting

  • Ischial spine: superior to tuberosity; important landmark (narrows outlet through pelvis through which the baby passes)

  • Greater sciatic notch: allows blood vessels and sciatic nerve to pass posteriorly to thigh (buttock injections should be far from this area!!!)

Hip Bones: Fusion of 3 Bones

Pubis (Fig. 5.26, p.162)

  • Pubis: most anterior portion of coxal bone

  • Obturator foramen: allows blood vessels and nerves to pass to the anterior part of thigh

  • A bone of bar from the rami of the pubis anteriorly & ischium posteriorly surrounds this

  • Pubic symphysis: fusion of both pubic bones, forming this cartilaginous joint

Hip Bones: Fusion of 3 Bones

Acetabulum (Fig. 5.26, p.162)

  • Deep socket that is the fusion of the ilium, ischium, and pubis

  • Receives the head of the thigh bone (femur)

Two Pelvic Regions

Fig. 5.26, p. 162

  • False pelvis: superior to true pelvis; medial to flaring ilia

  • True pelvis: inferior to flaring ilia; surrounded by bone

  • For women, the true pelvis MUST be large enough for the baby’s head to pass through

  • The dimensions of the outlet (inferior) and inlet (superior) must be carefully measured

Chracteristics of the FEMALE

pelvis (Fig. 5.26 (c), p.162)

  • Inlet is larger & more circular

  • Shallower, and the bones are lighter and thinner

  • Ilia flare more laterally

  • Sacrum is shorter & less curved

  • Ischial spines are shorter and father apart (creating larger outlet)

  • Pubic arch is more rounded (the pubic arch is greater)

Foot

Fig. 5.28, p.165

  • Two functions: supports body weight and acts as a lever to propel our bodies as we walk or run

  • Tarsus: posterior of foot; 7 tarsal bones

  • 2 largest carry most of the body weight: the calcaneus (heelbone) and talus (lied between the tibia and calcaneus)

  • Metatarsals: sole of the foot; 5 bones

  • Phalanges: toes; 14 bones

  • All toes have 3 bones, except the big toe (2 bones)

Arches of the Foot

Fig. 5.29, p.165

  • Bones are arranged to form 3 arches

  • 2 arches are longitudinal (one medial and one lateral), and 2 arch is transverse

  • The ligaments and tendons in the foot help secure the foot bones, but allow a certain amount of give or springiness

  • Weak arches are referred to as “fallen arches” or “flat feet”

Joints

P.165-173

Joints (Articulations)

  • Sites where 2 or more bones meet

  • Hyoid bone-only unarticulated bone in body

  • Two functions:

  • Hold bones in place

  • Give rigid skeleton mobility

  • Two ways joints are classified:

  • Functionally

  • Structurally

Funtional Classifications of Joints

  • Synarthroses: immovable

  • Mostly restricted to axial skeleton

  • Amphiarthroses: slightly movable

  • Mostly restricted to axial skeleton

  • Diarthroses: freely movable

  • Predominate in the limbs

Structural Classification of Joints

Fig. 5.30, p.168 & Table 5.3, p.169

  • Fibrious: fibrous tissue connects bones

  • Generally immovable (synarthroses)

  • Cartilaginous: cartilage connects bones

  • Generally slightly movable (amphiarthroses)

  • Synovial: joint cavity connects bones

  • Generally freely movable (diarthroses)

Fibrous Joints

  • United by fibrous tissue

  • Eg. Sutures in the skull (Fig. 5.30(a), p.168)

  • Irregular edges interlock and are bound by connective tissue fibers

  • Syndesmoses- fibers connecting bones are longer than in sutures; more “give” to the joint

  • Eg. Joint connecting the distal end of the tibia and fibula

Cartilaginous Joints

  • Bone ends are connected by fibrocartilage

  • Eg. of the slightly movable (amphiarthrotic) joints: pubis symphysis and intervertebral joints (Fif. 5.30 (e-d), p.168)

  • Syndchondroses: immovable cartilaginous joints (synarthrotic)

  • Eg. Epiphyseal plates and joints between first ribs & sternum (Fig. 5.30 (c), p.168)

Synovial Joints

Fig. 5.30 (f-h), p. 168

  • Bones articulate at a joint cavity filled with synovial fluid; eg. Limbs

  • 4 characteristics:

  • Articular (hyaline) cartilage covers bone ends

  • Joint surfaces enclosed by sleeves of fibrous c.t. (articular capsule), lined with a smooth synovial membrane

  • Articular capsule encloses joint vanity, which contains lubricating synovial fluid

  • Fibrous layer of capsule reinforced by ligaments

Bursae & Tendon Sheaths

  • Bags of lubricant closely associated with synovial joints (Fig. 5.32, p. 170)

  • Act like ball bearings to reduce friction

  • Bursae: flattened fibrous sacs lined with synovial membranes and containing a thin film of synovial fluid

  • Common where ligaments, muscles, skin, tendons, or bones rub together

  • Tendon sheaths: an elongated bursa; wrapped around a tendon subject to friction

Homeostatic Imbalance:

Dislocation

  • The bone is forced out of its normal position in the joint cavity

  • Reduction: process of returning the bone to its proper position

  • Should ALWAYS be done by a physician!!!

Homeostatic Imbalance

Bursitis&Sprain

  • Bursitis: “water on the knee”

  • Inflammation of bursae or synovial membranes in the patellar area

  • Sprain: Inflammation (or possible tearing) of the ligaments or tendons

  • Causes swelling

  • Slow to heal because tendons and ligaments are poorly vascularized

Homeostatic Imbalance:

Arthritis

  • Describe over 100 inflammatory or degenerative diseases that affect the joints

  • Most widespread crippling disease in the U>|S

  • All forms start with: pain, stiffness, & swelling of the joints

  • Different types of arthritis have different long-lasting effects

  • Acute forms: bacterial infections; treat with antibiotics

  • Synovial membrane thicken and fluid decreases=increased friction=PAIN

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