Lab Practical 2 Exam Review
Skeletal System Organization and Bone Tissue
The skeletal system serves essential bodily functions including structural support, protection of internal organs, facilitation of movement, mineral storage, and hematopoiesis.
The human skeleton is divided into two major anatomical divisions:
Axial skeleton: Forms the central longitudinal axis of the body; comprises the skull, vertebral column, and thoracic cage (ribs and sternum).
Appendicular skeleton: Comprises the upper and lower extremities and the girdles that attach them to the axial skeleton (pectoral girdle: clavicle and scapula; pelvic girdle: coxal bones).
Testing identification: Practical exams may present isolated bones (e.g., the clavicle) and require classification as either axial or appendicular.
Two general types of bone tissue compose osseous structures:
Compact bone (cortical bone): Dense, solid outer layer providing strength and protection.
Spongy bone (cancellous or trabecular bone): Porous, honeycomb-like internal network of trabeculae accommodating bone marrow.
Microscopic structure of bone tissue is primarily covered within histology units, though fundamental microscopic features remain possible exam material.
Bone Shape Classifications and Gross Anatomy
Bones are categorized into four primary shapes based on morphological criteria:
Long bones: Longer than they are wide, consisting of a shaft with expanded ends. Categorized examples include:
Humerus, radius, ulna, femur, tibia, and fibula.
Metacarpals (hand) and metatarsals (foot).
Phalanges (both manual and pedal digits, despite their small length).
Short bones: Roughly cube-shaped bones containing mostly spongy bone.
Carpals (wrist bones).
Tarsals (ankle bones).
Flat bones: Thin, flattened, and typically curved structures with two parallel layers of compact bone sandwiching spongy bone.
Scapula (classified as a flat bone despite possessing projecting processes).
Sternum, ribs, and cranial bones.
Irregular bones: Complex, specialized shapes that do not fit into the other categories.
Vertebrae.
Facial bones.
Pelvic/coxal bones and the sacrum.
Gross anatomy of a long bone (required for practical diagram labeling and fill-in-the-blank identification):
Diaphysis: The elongated, cylindrical central shaft of the bone.
Epiphysis: The expanded proximal and distal ends of the bone, capped with articular cartilage.
Medullary cavity: The central internal space running through the diaphysis, containing bone marrow.
Epiphyseal plate: The plate of hyaline cartilage located between the epiphysis and diaphysis in growing bones, later ossifying into the epiphyseal line in adults.
Cranial Bones, Markings, and Facial Bones
Calvarium: The cranial vault or skullcap; removal of the calvarium allows direct internal visualization of the floor of the cranial cavity, including the sphenoid and ethmoid bones.
Temporal bone landmarks:
Zygomatic process of the temporal bone: An anterior projection extending roughly halfway across the cheek arch to articulate with the temporal process of the zygomatic bone.
External auditory meatus: The external bony ear canal penetrating into the skull.
Mastoid process: A prominent rounded prominence situated immediately posterior and inferior to the ear canal.
Styloid process: A slender, needle-like projection pointing downwards beneath the mastoid process.
Occipital bone landmarks:
Foramen magnum: The large opening located on the inferior aspect of the occipital bone that serves as the passage for the spinal cord.
Internal cranial base landmarks:
Sphenoid bone: A central, bat-shaped bone spanning the floor of the middle cranial fossa.
Ethmoid bone: An anterior cranial bone characterized by small perforations (cribriform plate) and a generally rectangular appearance.
Facial bones and landmarks:
Mandible: The lower jawbone consisting of the horizontal body (bearing the lower teeth) and the ramus (the vertical/angular portion that articulates with the mandibular fossa of the temporal bone).
Zygomatic bone: The independent bone forming the prominence of the cheek ("apple of the cheek") and lateral orbital wall; distinct from the zygomatic process of the temporal bone.
Maxilla: The paired bone forming the upper jaw and central facial structure.
Lacrimal bones: Small bones positioned in the anterior medial wall of each orbit.
Nasal bones: Paired small bones forming the bridge of the nose.
Vomer: Thin bone forming the inferior portion of the nasal septum.
Orbital openings:
Optic canal: The round foramen located at the apex of the orbit transmitting the optic nerve.
Superior orbital fissure: An irregular, elongated cleft in the posterior orbit; excluded from direct practical exam identification.
Vertebral Column and Thoracic Cage
The vertebral column is organized into distinct anatomical regions with specific counts:
Cervical vertebrae: vertebrae ().
Thoracic vertebrae: vertebrae ().
Lumbar vertebrae: vertebrae ().
Sacrum: Formed by the fusion of sacral vertebrae.
Coccyx: Formed by the fusion of (typically ) rudimentary coccygeal vertebrae.
Thoracic cage rib classifications (comprising total pairs):
True ribs (vertebrosternal ribs): Pairs through ; each attaches directly to the sternum via its own individual costal cartilage.
False ribs: Pairs through ; they do not attach directly to the sternum.
Floating ribs (vertebral ribs): Pairs and ; a specific subset of false ribs that lack any anterior sternal connection.
Sternum landmarks:
Manubrium: The superior, broad triangular segment.
Body (gladiolus): The elongated, flat middle portion.
Xiphoid process: The small, pointed inferior projection.
Pectoral Girdle and Upper Extremity
Pectoral girdle: Composed of the clavicle and scapula, attaching the upper extremity to the axial trunk.
Scapula landmarks:
Superior border: The uppermost margin of the scapular body.
Glenoid cavity (glenoid fossa): The shallow lateral socket that articulates with the head of the humerus to form the glenohumeral (shoulder) joint, a multi-axial ball-and-socket joint.
Brachium (arm):
Humerus: The single bone of the brachium.
Head of the humerus: Hemispherical proximal articulation for the glenoid cavity.
Greater tubercle: Lateral, larger proximal prominence.
Lesser tubercle: Medial/anterior, smaller proximal prominence.
Trochlea: Medial, spool-shaped distal articular condyle for the ulna.
Antebrachium (forearm):
Radius: The lateral bone of the forearm (positioned along the thumb side); distinguished by a round, flat, disk-like proximal head.
Ulna: The medial bone of the forearm (positioned along the little finger side); distinguished by a prominent proximal hook-like shape formed by the olecranon and trochlear notch.
Manus (wrist and hand):
Carpals: The short bones comprising the wrist complex (individual names not tested on this practical).
Metacarpals: The long bones forming the palm of the hand; numbered starting laterally from the thumb (metacarpal ) to the pinky (metacarpal ).
Phalanges: The bones of the digits;
Digits each possess phalanges: proximal, middle, and distal.
Digit (pollex/thumb) possesses only phalanges: proximal and distal.
Pelvic Girdle and Lower Extremity
Pelvic girdle:
Coxal bone (hip bone or os coxae): Formed by the developmental fusion of three separate bones:
Ilium: The superior, broad flaring bone.
Ischium: The inferior, posterior bone situated directly beneath the ilium.
Pubis (pubic bone): The anterior, inferior bone.
Acetabulum: The deep lateral socket formed by the convergence of the ilium, ischium, and pubis; articulates with the head of the femur to form the hip joint (a ball-and-socket synovial joint).
Ilium specific landmarks:
Iliac crest: Superior thickened ridge of the ilium.
Greater sciatic notch: Large, deep posterior indentation beneath the posterior inferior iliac spine.
Sacroiliac joint: Articulation connecting the ilium of the pelvic girdle directly to the sacrum of the axial skeleton (does not involve lumbar vertebrae or the coccyx).
Thigh:
Femur: The single, heavy bone of the thigh.
Head of the femur: Smooth, spherical proximal articulation fitting into the acetabulum.
Neck of the femur: Constricted region connecting the head to the femoral shaft.
Patellar surface: Smooth, anterior distal depression between femoral condyles accommodating the patella.
Knee region:
Patella: The triangular kneecap; classified as a sesamoid bone.
Crural region (leg):
Tibia: The larger, medial weight-bearing bone of the leg (the shinbone); forms the medial malleolus (medial prominence of the ankle).
Fibula: The slender, lateral stabilizing bone of the leg; forms the lateral malleolus (lateral prominence of the ankle).
Pes (ankle and foot):
Tarsals: Ankle bones; two specific tarsals are required for practical examination:
Talus: Positioned directly between the medial malleolus of the tibia and lateral malleolus of the fibula; articulates superiorly with both leg bones.
Calcaneus: The large posterior tarsal forming the heel.
Metatarsals: The long bones forming the sole and arch; numbered beginning medially with the big toe (hallux) and moving laterally (metatarsal is located medial to metatarsal ).
Phalanges: The toe bones;
Digits each possess phalanges: proximal, middle, and distal.
Digit (hallux/big toe) possesses only phalanges: proximal and distal.
Articulations and Joint Classifications
Joints (articulations) are classified structurally into three categories based on the binding tissue and mobility:
Fibrous joints: United by dense fibrous connective tissue; lack a joint cavity; least movable joints (synarthroses). Example: Sutures of the skull.
Cartilaginous joints: Connected entirely by cartilage (hyaline cartilage or fibrocartilage); lack a joint cavity; permit slight movement (amphiarthroses). Examples: Intervertebral discs, pubic symphysis.
Synovial joints: Characterized by a fluid-filled synovial joint cavity enclosed by an articular capsule; freely movable (diarthroses); constitute the most movable joint category.
Six morphological types of synovial joints:
Ball-and-socket joints (e.g., glenohumeral/shoulder joint, coxal/hip joint).
Pivot joints (e.g., atlantoaxial joint, proximal radioulnar joint).
Saddle joints (e.g., carpometacarpal joint of the thumb).
Hinge joints.
Condylar (ellipsoid) joints.
Planar (gliding) joints.
Knee Joint Anatomy and Ligaments
Structural components: The knee joint is formed by the articulation between the distal femur and the proximal tibia, protected anteriorly by the patella.
Ligaments and internal knee structures required for testing:
Anterior cruciate ligament (ACL): Located intra-articularly; visible in an anterior view of the knee joint with the patella removed, traversing toward the anterior intercondylar area.
Posterior cruciate ligament (PCL): Located intra-articularly posterior to the anterior cruciate ligament.
Lateral meniscus: Crescent-shaped fibrocartilaginous pad resting on the lateral tibial plateau.
Medial meniscus: Crescent-shaped fibrocartilaginous pad resting on the medial tibial plateau.
Testing exclusions and clinical relevance:
Medial collateral ligament (MCL) and lateral collateral ligament (LCL) are not tested on this practical examination.
Clinical sports injury context: ACL tears are extremely prevalent in athletic injuries, whereas MCL injuries typically occur secondary to a direct lateral impact blow to the knee.
Body Movements and Kinematics
Flexion: An angular movement that decreases the angle between articulating bones.
Examples: Bending the elbow; bringing the neck forward so the chin approaches the chest; elevating the arm anteriorly at the shoulder.
Extension: An angular movement that increases the angle between articulating bones to return a body part to anatomical position.
Examples: Straightening the bent elbow; sitting upright with the head erect; resting the arms along the sides of the torso.
Hyperextension: Extension of a limb or joint beyond standard anatomical alignment.
Examples: Tilting the head backwards toward the ceiling; drawing the arm straight behind the body.
Dorsiflexion: Movement at the ankle elevating the superior surface of the foot and toes upward toward the sky or shin (standing on the heels).
Plantar flexion: Movement at the ankle pointing the foot and toes downward toward the ground (standing on the toes or depressing a pedal).
Abduction: Movement of a limb coronal/laterally away from the midline of the body (e.g., raising the upper or lower extremity out to the side).
Adduction: Movement of a limb toward the anatomical midline of the body (e.g., bringing an abducted arm or leg back inward).
Rotation: The turning of a bone around its own longitudinal axis.
Medial (internal) rotation: Anterior surface of the limb rotates inward toward the midline.
Lateral (external) rotation: Anterior surface of the limb rotates outward away from the midline.
Can occur at ball-and-socket joints (shoulder and hip) as well as pivot joints.
Protraction: Non-angular anterior movement in a horizontal plane.
Examples: Pushing the shoulders forward (as when pushing a door open); thrusting the mandible anteriorly.
Retraction: Non-angular posterior movement in a horizontal plane returning from protraction.
Examples: Pulling the scapulae/shoulders back to stand in upright military posture; pulling the mandible back.
Depression: Movement of a body part inferiorly in the coronal/sagittal plane.
Example: Lowering the mandible downward when yawning or opening the mouth.
Questions and Class Discussion
Q: What bone tissue types compose bone?
A: Spongy bone and compact bone.
Q: What bone shape category do the phalanges, metacarpals, and metatarsals belong to?
A: They are classified as long bones.
Q: How is the scapula classified despite its irregular processes?
A: It is classified as a flat bone.
Q: Where are irregular bones predominantly located?
A: In the vertebral column, the facial skeleton, and the pelvis (including the sacrum).
Q: What is the diaphysis of a long bone also known as?
A: The shaft.
Q: What process is located on the temporal bone that resembles another facial bone name?
A: The zygomatic process of the temporal bone.
Q: What prominent opening exists on the inferior aspect of the occipital bone, and what structure traverses it?
A: The foramen magnum; the spinal cord passes through it.
Q: How many cervical, thoracic, and lumbar vertebrae are there?
A: cervical, thoracic, and lumbar vertebrae.
Q: How many pairs of true, false, and floating ribs exist?
A: pairs of true ribs (pairs ), pairs of false ribs (pairs ), and pairs of floating ribs (pairs ).
Q: What three segments compose the sternum?
A: The manubrium, the body, and the xiphoid process.
Q: What bone articulates with the glenoid cavity of the scapula, and what type of joint is formed?
A: The head of the humerus; it forms a ball-and-socket (shoulder) joint.
Q: How can the radius and ulna be distinguished when laid out on a table?
A: The radius has a round, flat head and sits laterally on the thumb side; the ulna possesses a distinct hook-like proximal end (olecranon/trochlear notch) and sits medially on the little finger side.
Q: What three bones fuse to form the coxal bone?
A: The ilium, ischium, and pubis.
Q: What bone articulates with the acetabulum, and what joint does it create?
A: The head of the femur; it forms the hip joint (a ball-and-socket joint).
Q: Which bone is positioned superior to the ischium?
A: The ilium.
Q: What axial bone does the ilium articulate with?
A: The sacrum (forming the sacroiliac joint); it does not articulate with the lumbar vertebrae or the coccyx.
Q: Which crural bone is medial, and which is lateral?
A: The tibia is medial (shinbone, forms the medial malleolus); the fibula is lateral (forms the lateral malleolus).
Q: Which two tarsal bones are required for identification on the exam?
A: The talus (which sits directly between the malleoli articulating with the tibia and fibula) and the calcaneus (the heel bone).
Q: Where is metatarsal number located relative to metatarsal number ?
A: Metatarsal number is medial to metatarsal number .
Q: Which structural joint category contains sutures of the skull?
A: Fibrous joints.
Q: Which joint category is the most movable?
A: Synovial joints.
Q: What movement is lowering the mandible (as in yawning)?
A: Depression.
Q: What movement is lifting the toes while standing on the heels?
A: Dorsiflexion.
Q: What movement is bending the elbow or flexing the neck so the chin approaches the chest?
A: Flexion.
Laboratory Resources and Study Curriculum
Chapter 6 lab file contains a dedicated section labeled "resource lab videos" at the very end.
These resource videos discuss specific osteological structures (e.g., greater and lesser tubercles of the humerus) and provide an alternative when students cannot access physical models in the library lab.
Articulations and joints are primarily addressed in appendicular video modules rather than isolated joint recordings.
Additional external study references:
A -minute introductory overview video covering joint classifications.
Crash Course Anatomy videos providing supplemental walkthroughs of structural anatomy.
Bone boxes are maintained in the lab setting for hands-on tactile review of isolated bones.
Upcoming curricular modules:
Chapter 7 Lab covers the muscular system.
Students should prioritize the document "Muscles List Revised," which explicitly correlates each required muscle with its specific physiological action.
The nervous system lab follows the muscular system and is comparatively more straightforward than muscle origin, insertion, and action identification.