Lecture 9: The Appendicular Skeleton

Vocabulary flashcards covering key bones, joints, and developmental concepts of the appendicular skeleton as presented in Lecture 9.

Appendicular Skeleton

Portion of the skeleton consisting of 126 bones of the limbs and their supporting girdles that connect to the trunk.

Pectoral Girdle

Set of bones (clavicle and scapula) that attach the upper limb to the axial skeleton; provides a flexible shoulder joint.

Clavicle (Collarbone)

S-shaped bone whose sternal end articulates with the manubrium and whose acromial end articulates with the scapula; braces the shoulder.

Scapula (Shoulder Blade)

Flat triangular bone that ‘floats’ on the posterior rib surface; features the acromion and glenoid cavity.

Glenoid Cavity

Lateral scapular depression that receives the head of the humerus to form the glenohumeral joint.

Glenohumeral Joint

Shoulder articulation between the glenoid cavity of the scapula and the head of the humerus.

Acromioclavicular Joint

Articulation between the acromion of the scapula and the acromial end of the clavicle.

Humerus

Single bone of the brachium; long bone with anatomical and surgical necks; distally presents trochlea and capitulum.

Trochlea

Medial condyle of the distal humerus that articulates with the ulna.

Capitulum

Lateral condyle of the distal humerus that articulates with the head of the radius.

Ulna

Medial bone of the forearm featuring the olecranon and coronoid processes; forms distal radioulnar joint with the radius.

Olecranon Process

Proximal projection of the ulna that forms the elbow’s point and articulates with the humerus.

Coronoid Process

Anterior projection of the ulna just below the olecranon; locks into the trochlea during flexion.

Radius

Lateral forearm bone; its head articulates with the capitulum; widened distally to form most of the wrist joint.

Carpal Bones

Eight wrist bones arranged in two rows: scaphoid, lunate, triquetrum, pisiform (proximal) and trapezium, trapezoid, capitate, hamate (distal).

Metacarpals

Five long bones of the palm that articulate proximally with carpals and distally with proximal phalanges.

Phalanges (Hand)

Four fingers contain three phalanges each (proximal, middle, distal); the pollex has two (proximal, distal).

Pelvic (Hip) Girdle

Paired coxal bones that attach lower limbs, transmit body weight, and protect pelvic organs; less mobile but more stable than pectoral girdle.

Coxal (Hip) Bone

Bone formed by fusion of ilium, ischium, and pubis.

Ilium

Superior region of the coxal bone; auricular surface articulates with the sacrum at the sacroiliac joint.

Ischium

Posteroinferior part of the hip bone.

Pubis

Anterior part of the hip bone; two pubic bones meet at the pubic symphysis.

Acetabulum

Cup-like lateral socket of the hip bone that articulates with the femoral head forming the coxal joint.

Sacroiliac Joint

Articulation between the auricular surface of the ilium and the sacrum.

Pubic Symphysis

Fibrocartilaginous joint uniting the two pubic bones anteriorly.

Obturator Foramen

Large opening between ischium and pubis for passage of blood vessels and nerves.

Femur

Largest, strongest bone forming the thigh; articulates proximally with acetabulum and distally with tibia and patella.

Patella

Largest sesamoid bone embedded in the quadriceps tendon; posterior surface articulates with femoral condyles.

Tibia

Large medial, weight-bearing bone of the lower leg; has two condyles that meet the femur and inferior surface that forms part of the ankle.

Fibula

Thin, non-weight-bearing lateral bone of the leg; important for muscle attachment; articulates with tibia but not femur.

Interosseous Membrane

Fibrous sheet that connects the shafts of tibia and fibula (and radius and ulna).

Tarsal Bones

Seven ankle bones: talus, calcaneus, navicular, cuboid, and three cuneiforms (medial, intermediate, lateral).

Talus

Superior tarsal bone that receives body weight and articulates with the tibia.

Calcaneus

Heel bone; largest tarsal bearing body weight with the talus.

Metatarsals

Five long bones (I–V) forming the distal foot; head of metatarsal I creates the ball of the foot.

Phalanges (Foot)

Toes contain 14 bones; hallux has two (proximal, distal), other toes have three (proximal, middle, distal).

Hallux

Great toe; contains only proximal and distal phalanges.

Arches of the Foot

Lateral longitudinal, medial longitudinal, and transverse arches that distribute body weight and provide springiness.

Fontanelles

Unossified fibrous membranes between fetal skull bones (anterior, posterior, mastoid, sphenoidal) allowing birth and brain growth.

Cleft Palate

Congenital absence of medial fusion of the right and left halves of the palate.

Primary Curvatures

Thoracic and sacral spinal curves present at birth, giving the infant spine a posteriorly convex C-shape.

Secondary Curvatures

Cervical and lumbar spinal curves that develop after birth (as child lifts head and walks), convex anteriorly.

Sesamoid Bone

Bone formed within a tendon; the patella is the largest example.

Intervertebral Disc Degeneration

Age-related thinning and dehydration of discs, increasing risk of herniation and height loss.