Lab 8 is about finding and naming the major skeletal muscles on models and diagrams, front and back, head to ankle. You will also be expected to read a muscle's name like a set of clues. This review drills each body region with labeled diagrams, then runs a timed practical where you type the names yourself.
Your lab manual wins. Lab sections vary in which models, slides, and terms they use. If anything here differs from your lab handout or what your instructor emphasized, go with your lab material and tell your tutor so this review can be updated.
Concept Review
Muscle names look intimidating until you notice they are built from a short list of clues. Most names combine two or three of them. Decode the name first and you already know roughly where the muscle sits and what it does, which is exactly what a lab practical rewards.
| Clue in the name | What it tells you | Examples |
|---|---|---|
| Location | The bone or body region it lies over | temporalis (temporal bone), tibialis anterior (front of tibia), brachialis (arm), intercostals (between ribs), frontalis |
| Shape | What it looks like | deltoid (triangle), trapezius (trapezoid), rhomboid (diamond), serratus (saw-toothed), orbicularis (ring) |
| Size | Relative size or length | maximus / medius / minimus, major / minor, longus / brevis, latissimus (widest) |
| Fiber direction | Direction the fibers run relative to the midline | rectus (straight, parallel to midline), transversus (across), oblique (on a slant) |
| Number of origins | How many heads the muscle has | biceps (2), triceps (3), quadriceps (4) |
| Attachments | Origin and insertion, usually origin first | sternocleidomastoid (sternum + clavicle → mastoid process), brachioradialis (arm → radius), coracobrachialis |
| Action | The movement it produces | flexor, extensor, adductor, levator (elevates), depressor, pronator, supinator, tensor |
Try it: flexor carpi ulnaris = action (flexes) + location (carpus = wrist) + location (ulnar side). So it flexes the wrist and sits on the pinky side of the forearm. Extensor digitorum longus = extends the digits (here, the toes) and is the long one.
Spelling counts. Many practicals take points off for misspelling. The usual trouble spots: sternocleidomastoid, gastrocnemius, semimembranosus vs semitendinosus, tensor fasciae latae, rectus abdominis (not "abdominus").
Concept Review
| Muscle | Where to find it on the model | Identifying feature | Main action |
|---|---|---|---|
| Frontalis (frontal belly of epicranius) | Forehead | Vertical fibers; joins the galea aponeurotica above | Raises eyebrows, wrinkles forehead |
| Occipitalis (occipital belly) | Back of the skull | Other half of epicranius; linked to frontalis by the galea aponeurotica | Pulls scalp backward |
| Orbicularis oculi | Ring around the eye | Circular fibers | Closes the eye (blink, squint) |
| Orbicularis oris | Ring around the mouth | Circular fibers in the lips | Closes and purses lips ("kissing muscle") |
| Zygomaticus (major and minor) | Cheekbone to corner of mouth | Diagonal strap | Smiling: lifts the corner of the mouth |
| Buccinator | Cheek, deep, between masseter and mouth | Horizontal fibers | Compresses cheek (whistling, blowing, keeps food on the teeth) |
| Masseter | Over the angle of the mandible | Thick, rectangular; zygomatic arch to mandible | Elevates mandible (prime mover of chewing) |
| Temporalis | Side of skull above the ear | Fan shape converging under the zygomatic arch | Elevates and retracts mandible |
| Sternocleidomastoid | Side of neck, diagonal | From sternum + clavicle up to the mastoid process behind the ear | One side: turns head to the opposite side; both: flex neck |
| Platysma | Anterior neck, very thin sheet | Superficial, over the front of the neck to the mandible | Tenses neck skin, depresses mandible / lower lip |
| Muscle | Where | Identifying feature | Main action |
|---|---|---|---|
| Pectoralis major | Chest | Large fan from sternum and clavicle to the humerus | Flexes, adducts, medially rotates the arm |
| Pectoralis minor | Deep to pec major | Small; ribs 3–5 to the coracoid process | Pulls scapula forward and down |
| Serratus anterior | Lateral chest wall below the axilla | Finger-like (saw-tooth) slips on the ribs | Protracts scapula ("boxer's muscle") |
| Rectus abdominis | Anterior abdomen, either side of the linea alba | Vertical; crossed by tendinous intersections ("six-pack") | Flexes the trunk |
| External oblique | Lateral abdomen, most superficial | Fibers run down and in (hands in front pockets) | Flexes and rotates trunk; compresses abdomen |
| Internal oblique | Deep to external oblique | Fibers at right angles to the external oblique (up and in) | Same as external oblique |
| Transversus abdominis | Deepest abdominal layer | Horizontal fibers | Compresses abdominal contents |
| External / internal intercostals | Between the ribs | External run down and forward; internal at right angles | External: elevate ribs (inspiration); internal: forced expiration |
| Diaphragm | Floor of the thoracic cavity | Dome with a central tendon | Prime mover of inspiration |
| Trapezius | Upper back and back of the neck | Kite / trapezoid shape (both sides together) | Elevates, retracts, depresses scapula; extends head |
| Latissimus dorsi | Lower back, sweeping up to the axilla | Broadest back muscle | Extends, adducts, medially rotates the arm |
| Rhomboids (major and minor) | Between spine and medial border of scapula, deep to trapezius | Diamond-shaped, fibers slanting down and out | Retract (adduct) and elevate scapula |
| Erector spinae | Along the vertebral column, deep | Three columns: iliocostalis, longissimus, spinalis | Extends the vertebral column |
Deep muscles on a model: internal oblique, transversus abdominis, pectoralis minor, intercostals, diaphragm, and the rhomboids are usually seen only on a model with removable layers or on one side of a dissected torso. If your model has a "peeled" side, practice both sides.
Label It · Face & Neck
Click a numbered pin (or its row), choose the structure it points to, then press Check answers. Wrong answers show the correction in green.
Label It · Anterior Body
Pins sit on one side of the body or the other; the muscles are the same on both sides. Click a numbered pin (or its row), choose the muscle, then press Check answers.
Label It · Posterior Body
The left half of this figure shows the superficial layer. On the right half, trapezius and latissimus dorsi have been removed to show the deeper back muscles. Click a pin, choose the muscle, then press Check answers.
Concept Review
| Muscle | Where | Identifying feature | Main action |
|---|---|---|---|
| Deltoid | Caps the shoulder | Triangular; inserts on the deltoid tuberosity | Prime mover of arm abduction |
| Supraspinatus (SITS) | Supraspinous fossa, above the scapular spine | Tendon passes under the acromion to the greater tubercle | Starts abduction |
| Infraspinatus (SITS) | Infraspinous fossa, below the spine | Fills most of the posterior scapula | Lateral rotation |
| Teres minor (SITS) | Lateral border of scapula, upper part | Narrow band just below infraspinatus | Lateral rotation |
| Subscapularis (SITS) | Anterior (costal) surface of scapula | Only cuff muscle on the front; inserts on the lesser tubercle | Medial rotation |
| Teres major (NOT cuff) | Inferior angle of scapula to the humerus | Thicker, lower than teres minor | Extends, adducts, medially rotates arm |
| Biceps brachii | Anterior arm, superficial | Two heads; tendon to the radial tuberosity | Flexes elbow; supinates forearm |
| Brachialis | Anterior arm, deep to biceps | Peeks out on both sides of the lower biceps | Prime mover of elbow flexion |
| Brachioradialis | Lateral forearm, from humerus to radial styloid | Forms the lateral edge of the forearm | Flexes elbow (best with thumb up) |
| Triceps brachii | Entire posterior arm | Long, lateral, and medial heads; tendon to the olecranon | Prime mover of elbow extension |
Orientation trick: find the thumb first. Anything with radialis is on the thumb side; anything with ulnaris is on the pinky side. Then decide palm side (flexor) or back side (extensor).
Label It · Rotator Cuff
Remember SITS: Supraspinatus, Infraspinatus, Teres minor, Subscapularis. Bony landmarks are pinned too. Click a pin, choose, then press Check answers.
Label It · Arm & Forearm
In the anterior view the thumb side (lateral) is on your left; in the posterior view it is on your right. Click a pin, choose, then press Check answers.
Concept Review
| Muscle / group | Where | Identifying feature | Main action |
|---|---|---|---|
| Iliopsoas (iliacus + psoas major) | Groin, deep in the upper anterior thigh | Emerges under the inguinal ligament, lateral to pectineus | Prime mover of hip flexion |
| Tensor fasciae latae | Upper lateral thigh | Short belly that joins the iliotibial tract | Flexes and abducts hip |
| Sartorius | Diagonal across the anterior thigh | Longest muscle in the body; ASIS to medial tibia | Flexes, abducts, laterally rotates hip ("tailor's position") |
| Quadriceps femoris: rectus femoris, vastus lateralis, vastus medialis, vastus intermedius | Anterior thigh | Rectus femoris down the middle; vastus lateralis on the side; vastus medialis teardrop above medial knee; vastus intermedius hidden under rectus femoris | Extend the knee (rectus femoris also flexes the hip) |
| Adductor group: adductor longus, brevis, magnus; pectineus; gracilis | Medial thigh | Gracilis is the thin strap along the medial edge | Adduct the thigh |
| Gluteus maximus | Buttock | Largest, most superficial gluteal | Prime mover of hip extension |
| Gluteus medius | Upper lateral buttock, partly under maximus | Fan above and lateral to gluteus maximus | Abducts hip; keeps pelvis level when walking |
| Hamstrings: biceps femoris, semitendinosus, semimembranosus | Posterior thigh | Biceps femoris is lateral; the two "semi" muscles are medial | Flex knee, extend hip |
| Tibialis anterior | Anterior leg, just lateral to the tibial shin | Tendon crosses the front of the ankle to the medial foot | Dorsiflexes and inverts the foot |
| Extensor digitorum longus | Anterior leg, lateral to tibialis anterior | Tendons fan out to toes 2–5 | Extends toes, dorsiflexes |
| Fibularis (peroneus) longus | Lateral leg | Tendon passes behind the lateral malleolus | Everts and plantar flexes the foot |
| Gastrocnemius | Superficial calf | Two heads (medial and lateral) forming the calf bulge | Plantar flexes foot; flexes knee |
| Soleus | Deep to gastrocnemius | Flat; visible on both sides below the gastrocnemius | Plantar flexes foot |
| Calcaneal (Achilles) tendon | Back of the ankle | Shared tendon of gastrocnemius and soleus to the calcaneus | (transmits plantar flexion) |
Naming note: newer texts say fibularis; many models and older manuals say peroneus. Both are correct. The same goes for calcaneal tendon / Achilles tendon and iliotibial tract / iliotibial band.
Label It · Lower Limb (Anterior)
These pins are all on the anterior view (left panel); lateral is on your left. Click a pin, choose, then press Check answers.
Label It · Lower Limb (Posterior)
These pins are all on the posterior view (right panel); lateral is on your right. Click a pin, choose, then press Check answers.
Check Yourself
Two tries per question. Your first-try score shows at the end.
Rapid Recall
Say the answer out loud, then tap the card to check. Shuffle and go again until every card is automatic.
Practical Simulation
This runs like a real lab practical: one structure or question per station, a timer, and you type the answer — no word bank. Spelling counts on most practicals, so spell it fully. Your score and every correct answer appear at the end.
20 stations · 50 seconds each · stations come in random order every attempt.
| # | Station | Your answer | Correct |
|---|
Watch Out
| The mistake | The fix |
|---|---|
| Writing "teres major" as a rotator cuff muscle | The cuff is SITS. Teres minor is in; teres major is not. |
| Mixing up the two "semi" hamstrings | SemiTendinosus has the long Tendon and is superficial; semiMembranosus is deeper and flatter. |
| Calling the lateral forearm muscle "brachialis" | Brachialis is in the arm, deep to biceps. The lateral forearm muscle is brachioradialis. |
| Naming the wrong side on a model | Lateral and medial are always relative to the model's own anatomical position. Find the thumb (radial, lateral) first. |
| Labeling the superficial back muscle on the deep side of the model | On a "half-peeled" model, the side without trapezius shows rhomboids, levator scapulae, supraspinatus, and erector spinae. |
| Spelling: "gastrocnemus," "sternocleidomastoids," "rectus abdominus" | Gastrocnemius, sternocleidomastoid (singular), rectus abdominis. Practice by typing them in the practical. |
| Writing only "quadriceps" when asked for a specific muscle | If a pin is on one muscle, name the muscle (e.g., vastus lateralis). Give the group name only when the question asks for the group. |
| Forgetting vastus intermedius exists | It is hidden under rectus femoris, but it still counts as one of the four quadriceps. |
Cheat Sheet
Print it or screenshot it for a last look before the lab.
| Topic | Know this |
|---|---|
| Naming clues | Location, shape, size, fiber direction, number of origins, attachments, action |
| Face | Frontalis (forehead), orbicularis oculi (eye ring), zygomaticus (smile), orbicularis oris (mouth ring), buccinator (cheek), masseter (jaw angle), temporalis (fan above ear) |
| Neck | Sternocleidomastoid (sternum + clavicle to mastoid), platysma (thin front sheet), trapezius (back) |
| Chest & abdomen | Pectoralis major (minor deep), serratus anterior (saw teeth), rectus abdominis, external oblique, internal oblique, transversus abdominis |
| Breathing | Diaphragm (prime mover of inspiration), external and internal intercostals |
| Back | Trapezius, latissimus dorsi; deep: rhomboids, levator scapulae, erector spinae |
| Rotator cuff (SITS) | Supraspinatus (above spine), infraspinatus (below spine), teres minor (lateral border), subscapularis (anterior). Teres major is NOT cuff. |
| Arm | Deltoid; biceps brachii (2 heads), brachialis (deep to biceps); triceps brachii (3 heads, back) |
| Forearm | Anterior flexors: FCR, palmaris longus, FCU (+ brachioradialis lateral). Posterior extensors: ECRL, ECRB, extensor digitorum, ECU |
| Hip | Iliopsoas (front), gluteus maximus, gluteus medius, tensor fasciae latae |
| Anterior thigh | Sartorius (diagonal); quadriceps: rectus femoris, vastus lateralis, vastus medialis, vastus intermedius (deep) |
| Medial thigh | Adductor longus, brevis, magnus; pectineus; gracilis (thin medial strap) |
| Posterior thigh | Hamstrings: biceps femoris (lateral), semitendinosus, semimembranosus (medial) |
| Leg | Anterior: tibialis anterior, extensor digitorum longus. Lateral: fibularis (peroneus) longus. Posterior: gastrocnemius, soleus, calcaneal (Achilles) tendon |
Debrief
You can now find and name the major skeletal muscles from head to ankle. Lab 9 builds directly on this: for each of these muscles, you will learn what it does at its joint and which muscle opposes it.
💭 Before the real thing: run the practical simulation until you score 90% or better twice in a row. Then do it once with the timer on.