The musculoskeletal unit has a large identification load: bones, processes, fossae, muscles, origins, insertions, and movements. This packet gives students and graders a shared vocabulary and explicit spelling rules for that work.
By the end of the musculoskeletal unit, a student should be able to:
Bones, markings, muscles, joints (Pages 2–5)
Bones, muscles (action), joints (movement) (Page 6)
Bone, hyaline cartilage, skeletal muscle (Page 7)
Palpation and range-of-motion observation (Page 8)
Weekly checklist applied across the 4-week unit (Page 9)
Musculoskeletal stations on the term-end practical (Page 10)
Most undergraduate A&P programs do not dissect for the musculoskeletal unit (cadavers are rare and prosections are pre-prepared). The R4 rubric is therefore applied to a performance task, palpation and range-of-motion on a partner, instead of to a dissection. The rubric structure is identical: observed live, scored binary, repeatable on a different anatomical region if needed.
| Canonical answer | Accepted synonyms | Spelling rule / common confusion |
|---|---|---|
| Skull | ||
| Frontal bone | (none) | Distinguish from frontal lobe ā not yet (different structure type) |
| Parietal bone | (none) | Side required if pin is on one |
| Temporal bone | (none) | Distinguish from temporal lobe ā not yet |
| Occipital bone | (none) | ā |
| Sphenoid bone | (none) | "Sphenoid" passes; "sphenoidal" passes |
| Ethmoid bone | (none) | "Ethmoid" passes; "ethmoidal" passes |
| Maxilla | Maxillary bone | "Mandible" ā not yet (different bone) |
| Mandible | (none) | Same rule |
| Zygomatic bone | Cheekbone, malar bone | Confusion with zygomatic process of temporal ā escalate if pin is on the process |
| Foramen magnum | (none) | Distinguish from foramen ovale ā not yet |
| Mastoid process | (none) | "Mastoid" alone passes if pin is unambiguous |
| Styloid process (temporal) | (none) | Specify bone if multiple styloid processes are pinned (also on radius/ulna) |
| Vertebral column | ||
| Cervical vertebra (C1āC7) | (none) | Number required if pinned individually; "cervical" alone passes only on regional questions |
| Atlas (C1) | First cervical vertebra | Distinguish from axis ā not yet |
| Axis (C2) | Second cervical vertebra | Same rule |
| Thoracic vertebra (T1āT12) | (none) | Distinguish from cervical/lumbar by transverse facets and spinous process angle |
| Lumbar vertebra (L1āL5) | (none) | Distinguish by larger body and absent transverse foramina |
| Sacrum | (none) | "Sacrium" ā not yet (spelling is content, distinct from "sacral") |
| Coccyx | Tailbone (informal but recognized) | "Coccus" ā not yet (different word) |
| Spinous process | (none) | Distinguish from transverse process ā not yet |
| Transverse process | (none) | Same rule |
| Vertebral foramen | (none) | Distinguish from intervertebral foramen ā not yet (vertebral = within one vertebra; intervertebral = between two) |
| Thoracic cage | ||
| Sternum (specify region) | Manubrium, body (gladiolus), xiphoid process | "Sternum" alone ā escalate if pin is on a specific region |
| True rib (1ā7) | Vertebrosternal rib | Distinguish from false ā not yet |
| False rib (8ā10) | Vertebrochondral rib | Same rule |
| Floating rib (11ā12) | Vertebral rib | Same rule |
| Canonical answer | Accepted synonyms | Spelling rule / common confusion |
|---|---|---|
| Pectoral girdle & upper limb | ||
| Clavicle | Collarbone (informal but recognized) | "Clavical" passes (phonetic) |
| Scapula | Shoulder blade (informal) | "Scapular" ā not yet (adjective form) |
| Acromion process | Acromion | Distinguish from coracoid process ā not yet |
| Coracoid process | (none) | Same rule |
| Glenoid cavity | Glenoid fossa | "Glenoid" alone passes |
| Humerus | (none) | "Humorous" ā not yet (different word) |
| Head of humerus | Humeral head | Distinguish from greater tubercle ā not yet |
| Greater tubercle (humerus) | Greater tuberosity | Distinguish from lesser tubercle ā not yet |
| Deltoid tuberosity | (none) | "Tubercle" vs "tuberosity" ā both sometimes accepted, but the canonical form is "tuberosity" |
| Medial epicondyle (humerus) | (none) | Side required (distinguish from lateral) |
| Lateral epicondyle (humerus) | (none) | Same rule |
| Olecranon fossa | (none) | Distinguish from coronoid fossa ā not yet |
| Radius | (none) | Confusion with ulna ā not yet (radius is on the thumb side) |
| Ulna | (none) | Confusion with radius ā not yet (ulna is on the pinky side) |
| Olecranon process | Olecranon | "Elbow" ā not yet (informal, not the bone marking) |
| Carpal bones (specify name) | "Carpals" alone passes only on regional questions | If pin is on one bone (e.g. scaphoid, lunate), name required |
| Metacarpals (IāV) | Metacarpal bones | Number required if pinned individually |
| Phalanges (specify hand/foot) | "Phalanx" (singular) | Hand vs foot required if ambiguous |
| Pelvic girdle & lower limb | ||
| Os coxae (hip bone) | Coxal bone, innominate bone, hip bone | "Pelvis" ā not yet (pelvis is the assembled girdle, not one bone) |
| Ilium | (none) | Distinguish from ileum (small intestine) ā not yet (different word) |
| Ischium | (none) | "Ishium" passes (phonetic) |
| Pubis | Pubic bone | Distinguish from pubic symphysis (joint) ā not yet if pin is on bone |
| Acetabulum | (none) | "Acetabulum" must include the full word |
| Iliac crest | (none) | Distinguish from ASIS ā not yet (anterior superior iliac spine is a distinct landmark) |
| Anterior superior iliac spine | ASIS | "Iliac spine" alone ā not yet (must specify which spine) |
| Femur | Thigh bone (informal but recognized) | ā |
| Head of femur | Femoral head | ā |
| Greater trochanter | (none) | Distinguish from lesser trochanter ā not yet |
| Patella | Kneecap (informal but recognized) | "Patela" passes (phonetic) |
| Tibia | Shin bone (informal but recognized) | Confusion with fibula ā not yet (tibia is medial and weight-bearing) |
| Fibula | (none) | Same rule |
| Medial malleolus | (none) | Side required; medial malleolus is on tibia, lateral malleolus is on fibula |
| Tarsal bones (specify name) | "Tarsals" alone passes only on regional questions | If pin is on talus, calcaneus, etc., name required |
| Calcaneus | Heel bone (informal but recognized) | ā |
| Talus | (none) | Distinguish from calcaneus ā not yet |
High-yield muscle list. Muscles outside this list may appear on the practical, but the controlled vocabulary below is what TAs grade against without escalation.
| Canonical answer | Accepted synonyms | Spelling rule / common confusion |
|---|---|---|
| Head & neck | ||
| Frontalis | Frontal belly of occipitofrontalis | ā |
| Orbicularis oculi | (none) | Distinguish from orbicularis oris ā not yet |
| Orbicularis oris | (none) | Same rule |
| Masseter | (none) | "Masetter" passes (phonetic) |
| Sternocleidomastoid | SCM | "Sterno-cleido-mastoid" with hyphens passes |
| Trapezius | Traps (informal) | ā |
| Trunk | ||
| Pectoralis major | (none) | Distinguish from pectoralis minor ā not yet (size matters) |
| Pectoralis minor | (none) | Same rule |
| Latissimus dorsi | Lats (informal) | "Latissmus" passes (phonetic) |
| Rectus abdominis | (none) | "Recti abdominis" ā not yet (Latin plural, but anatomical name is singular) |
| External oblique | (none) | Distinguish from internal oblique ā not yet |
| Internal oblique | (none) | Same rule |
| Transverse abdominis | Transversus abdominis | Both forms accepted |
| Diaphragm | (none) | "Diaphram" passes (phonetic) |
| Erector spinae (group) | (none) | Individual muscles (iliocostalis, longissimus, spinalis) accepted |
| Upper limb | ||
| Deltoid | (none) | "Deltoideus" ā escalate (Latin form, technically correct) |
| Biceps brachii | Biceps (with location implied) | "Bicep" ā escalate (anatomically the muscle has two heads, name is plural) |
| Triceps brachii | Triceps | Same rule as biceps |
| Brachialis | (none) | Distinguish from biceps brachii ā not yet (deeper, single-joint flexor) |
| Brachioradialis | (none) | "Brachio-radialis" with hyphen passes |
| Pronator teres | (none) | Distinguish from supinator ā not yet |
| Flexor carpi radialis | (none) | Distinguish from ulnaris (medial vs lateral) ā not yet |
| Flexor carpi ulnaris | (none) | Same rule |
| Extensor digitorum | Extensor digitorum communis | Distinguish from flexor digitorum ā not yet |
| Canonical answer | Accepted synonyms | Spelling rule / common confusion |
|---|---|---|
| Lower-limb muscles | ||
| Gluteus maximus | (none) | Distinguish from medius/minimus ā not yet |
| Gluteus medius | (none) | Same rule |
| Iliopsoas | Iliacus + psoas major (acceptable as group) | ā |
| Sartorius | (none) | Longest muscle in the body ā useful identifier |
| Quadriceps femoris (group) | Quads (informal); rectus femoris, vastus lateralis, vastus medialis, vastus intermedius (any individual head accepted) | "Quadricep" ā escalate (singular form not standard) |
| Rectus femoris | (none) | Only quadriceps head crossing two joints ā useful identifier |
| Vastus lateralis | (none) | Distinguish from medialis/intermedius ā not yet |
| Hamstrings (group) | Biceps femoris, semitendinosus, semimembranosus (any individual accepted) | "Hamstring" singular ā not yet (the muscles are a group) |
| Biceps femoris | (none) | Distinguish from biceps brachii by location |
| Tibialis anterior | (none) | Distinguish from tibialis posterior ā not yet |
| Gastrocnemius | Gastroc (informal) | "Gastrocnemias" ā escalate (Latin plural, debatable) |
| Soleus | (none) | Distinguish from gastrocnemius ā not yet (soleus is deeper, single-joint) |
| Calcaneal tendon | Achilles tendon | Both accepted; "Achilles' tendon" with apostrophe also passes |
| Joint classifications | ||
| Synarthrosis (immovable) | Fibrous joint (most synarthroses) | Functional vs structural classification ā both accepted; example: skull suture |
| Amphiarthrosis (slightly movable) | Cartilaginous joint (most amphiarthroses) | Example: pubic symphysis, intervertebral disc |
| Diarthrosis (freely movable) | Synovial joint | Example: shoulder, hip, knee |
| Hinge joint | (none) | Example: elbow (humeroulnar), knee, ankle (talocrural) |
| Ball-and-socket joint | Spheroidal joint | Example: shoulder (glenohumeral), hip (acetabulofemoral) |
| Pivot joint | (none) | Example: atlantoaxial (C1āC2), proximal radioulnar |
| Saddle joint | (none) | Example: thumb (1st carpometacarpal) |
| Condyloid joint | Ellipsoidal joint | Example: wrist (radiocarpal), metacarpophalangeal |
| Gliding joint | Plane joint | Example: intercarpal, intertarsal |
For muscles, function is the primary action at the named joint. Origin and insertion are scored separately as their own R2 items on high-yield muscles. The standard joint-movement vocabulary follows.
| Muscle | Acceptable action statement (any one is sufficient) | What does NOT pass |
|---|---|---|
| Sternocleidomastoid | Unilaterally rotates the head to the opposite side; bilaterally flexes the neck | "Moves head" alone (must specify direction) |
| Pectoralis major | Adducts and medially rotates the humerus; flexes the humerus (clavicular head) | "Chest muscle" alone (location, not action) |
| Latissimus dorsi | Extends, adducts, and medially rotates the humerus | "Back muscle" alone (location, not action) |
| Deltoid | Anterior fibers flex and medially rotate the humerus; middle fibers abduct the humerus; posterior fibers extend and laterally rotate the humerus | "Lifts arm" alone (must indicate which fibers or which movement) |
| Biceps brachii | Flexes the elbow; supinates the forearm; weak shoulder flexor | "Bends arm" alone (must specify joint) |
| Triceps brachii | Extends the elbow; long head extends the shoulder | "Straightens arm" alone (must specify joint) |
| Rectus abdominis | Flexes the lumbar vertebral column (trunk flexion); compresses abdominal contents | "Sit-ups" alone (movement is correct, but joint must be named) |
| Gluteus maximus | Extends the hip; laterally rotates the hip; assists in trunk extension | "Sitting" alone (action of the muscle, not its purpose) |
| Quadriceps femoris | Extends the knee; rectus femoris also flexes the hip | "Kicks" alone (must specify joint) |
| Hamstrings | Flex the knee; extend the hip | "Bend leg" alone (must specify joint) |
| Tibialis anterior | Dorsiflexes the foot at the ankle; inverts the foot | "Lifts foot" alone (must indicate dorsiflexion) |
| Gastrocnemius | Plantarflexes the foot at the ankle; flexes the knee | "Pushes off the ground" alone (must indicate plantarflexion) |
The following terms are pre-approved for any joint where they apply. Side or axis of rotation may be required by the specific item.
| Flexion / Extension | Decrease / increase in joint angle | Hyperextension also accepted where anatomically possible |
| Abduction / Adduction | Movement away from / toward the midline | For digits: midline of the hand or foot, not the body |
| Medial / Lateral rotation | Internal / external rotation around the long axis | "Internal" / "external" rotation accepted as synonyms |
| Pronation / Supination | Forearm rotation: palm down / palm up | Forearm only; for foot use inversion / eversion |
| Dorsiflexion / Plantarflexion | Foot at the ankle: toes up / toes down | "Flexion" alone at the ankle ā not yet (ambiguous) |
| Inversion / Eversion | Sole of foot turned medially / laterally | Distinguish from dorsi/plantarflexion ā not yet |
| Circumduction | Conical movement combining flex/ext/abd/add | Specific to ball-and-socket and condyloid joints |
| Opposition / Reposition | Thumb-specific: thumb to fingertips and back | Saddle joint of the thumb only |
| Slide | Canonical identification | Two features required (any two from list) |
|---|---|---|
| Compact bone (ground or H&E) | Compact bone | Concentric lamellae arranged in osteons (Haversian systems) Ā· Central canal (Haversian canal) at the center of each osteon Ā· Lacunae containing osteocytes between lamellae Ā· Canaliculi radiating from lacunae |
| Hyaline cartilage | Hyaline cartilage | Glassy, homogeneous matrix Ā· Chondrocytes in lacunae, often in pairs (isogenous groups) Ā· Perichondrium at the tissue surface (if visible) Ā· No visible blood vessels in the matrix |
| Skeletal muscle (longitudinal section) | Skeletal muscle | Long, cylindrical, multinucleate fibers (cells) Ā· Nuclei at the periphery of the fiber, just under the sarcolemma Ā· Distinct cross-striations (alternating A and I bands) Ā· Fibers run in parallel |
| Skeletal muscle (cross-section) | Skeletal muscle, cross-section | Polygonal fiber profiles Ā· Multiple peripheral nuclei per fiber visible at the cell perimeter Ā· Bundles (fascicles) of fibers surrounded by perimysium Ā· Endomysium between individual fibers |
In place of a dissection rubric, this unit uses a performance task observed live during the lab session: palpation of named bony landmarks and demonstration of named joint movements on a partner. The structure is identical to a dissection rubric, observed live, scored binary, repeatable.
The musculoskeletal exam introduces practices relevant to later clinical work. R4 is graded with explicit attention to professionalism (consent, communication, comfort) alongside anatomical accuracy. The rubric is intended to prepare students for respectful, accurate assessment.
If the partner indicates discomfort verbally or non-verbally and the student does not respond, the TA pauses the assessment and delivers one direct correction. A second non-response in the same session is an automatic not yet and a referral to the coordinator for a one-on-one professionalism review before the repeat is offered.
The musculoskeletal unit is the first in many A&P sequences where students systematically learn anatomical drawing. Sketches should progress over the four weeks from rough silhouettes with labels to properly proportioned drawings with origin and insertion lines for high-yield muscles. The rubric does not grade artistic skill, only that the labeled structures are anatomically correct and the orientation is specified.
The musculoskeletal unit contributes 5 stations to the term-end capstone (one more than other units, reflecting the heavier identification load). Each station is 90 seconds and tests four judgments. The station passes at 3 of 4; excellence is 4 of 4.
ID per R1. Function: bone's role in protection or support. Clinical: one common pathology or fracture. Integration: relate to muscle that inserts or originates here.
Same four-judgment structure. Integration: relate to the joint(s) the bone participates in.
ID per R1. Function: primary action at the named joint. Clinical: one assessment maneuver or common strain. Integration: relate to nervous innervation (e.g. "deltoid is innervated by the axillary nerve") or the antagonist muscle.
ID: joint type by structure. Function: movements possible at that joint type. Clinical: one common injury or arthritic pattern. Integration: relate to the muscles that produce the named movement.
Performance station, observed live with a partner. ID: name of landmark or movement. Function: anatomical purpose. Clinical: state one normal or abnormal interpretation. Integration: relate to surrounding structures (nerve in the area, vessel landmark).
| Outcome per station | Counted as |
|---|---|
| 4 / 4 | Excellence (counts toward A bundle) |
| 3 / 4 | Pass (counts toward B and C bundles) |
| ⤠2 / 4 | Not yet (counts toward D bundle if attempted; no F-bundle credit) |
| No attempt | Not counted toward any bundle |
Student: ______________________________________ Section: _______________ Date: _______________ TA: _______________
| # | Item | ID (R1) | Function (R2) | Notes |
|---|---|---|---|---|
| 1 | Skull bone | P / NY | P / NY / ā | |
| 2 | Vertebral column item | P / NY | P / NY / ā | |
| 3 | Upper-limb bone | P / NY | P / NY / ā | |
| 4 | Upper-limb marking | P / NY | ā | |
| 5 | Lower-limb bone | P / NY | P / NY / ā | |
| 6 | Lower-limb marking | P / NY | ā | |
| 7 | Axial muscle | P / NY | P / NY / ā | |
| 8 | Upper-limb muscle | P / NY | P / NY / ā | |
| 9 | Lower-limb muscle | P / NY | P / NY / ā | |
| 10 | Joint type / movement vocabulary | P / NY | P / NY / ā |
| # | Slide | ID | ā„2 features | Notes |
|---|---|---|---|---|
| 11 | Compact bone | P / NY | P / NY | |
| 12 | Skeletal muscle (long. or x-section) | P / NY | P / NY |
| Item | Criterion | Met |
|---|---|---|
| P1 | Partner consent and positioning | P / NY |
| P2 | Landmarks correctly located | P / NY |
| P3 | Movement performed correctly (isolated) | P / NY |
| P4 | Communication and observation of comfort | P / NY |
| R4 | Overall (4 of 4 = pass) | P / NY |
ā No ā Yes, for item: __________
Tokens left this term after this session (choose one): ā 3 ā 2 ā 1 ā None left
P = Pass Ā· NY = Not yet Ā· ā = Not assessed Ā· Edge cases: circle, do not check, bring to coordinator at end of session.