Muscles Practical

frontalis

Forehead covering the frontal bone; raises eyebrows, wrinkles forehead.

procerus

Bridge of nose, between the eyebrows; Runs vertically down the nasal bridge; wrinkles skin over nose

Orbicularis oculi

Circling the orbit / eye; Circular sphincter muscle; closes eyelids tightly.

Nasalis

Across bridge & flared cartilage of nose; Directly covers the bridge and ala of the nose.

Levator labii superioris

Between lower orbit and upper lip; Lies immediately medial to the zygomaticus muscles; elevates upper lip.

Zygomaticus minor

Upper, thinner diagonal cheek strap; originates on zygomatic bone superior/medial to major; elevates upper lip.

Zygomaticus major

Lower, thicker diagonal cheek strap; Runs down toward corner of mouth; "smiling muscle".

Orbicularis oris

Circling the lips; Circular sphincter muscle; closes/puckers lips ("kissing muscle").

Buccinator

Deep wall of the cheek (under zygomaticus); Horizontal fibers compressing cheek against teeth (whistling/chewing).

Mentalis

Prominence of the chin; Paired vertical fibers on the chin apex; elevates/protrudes lower lip.

Temporalis

Elevates and retracts the mandible (closes jaw).

masseter

Superficial, thick rectangular muscle over the ramus of the jaw; Primary jaw elevator.

Lateral (External) Pterygoid

Visible when the masseter muscle is removed. Runs horizontally; Protracts mandible and opens jaw.

Medial (Internal) Pterygoid

Deep and vertical, running along the medial (interior) surface of the mandibular ramus; Synergist with masseter to elevate mandible.

Sternocleidomastoid (SCM)

Prominent strap crossing diagonally from the sternum/clavicle to the mastoid process behind the ear. Divides the neck into anterior and posterior triangles.

Scalene Group (Anterior, Middle, Posterior)

Deep muscle bundle exposed right in the posterior triangle, lateral to SCM and running down to Ribs 1 and 2.

skeletal muscle

Long, cylindrical, unbranched fibers with distinct cross-striations and multiple peripheral nuclei pressed against the edge.

cardiac muscle

Long, cylindrical, unbranched fibers with distinct cross-striations and multiple peripheral nuclei pressed against the edge.

smooth muscle

Non-striated, spindle-shaped (tapered) fibers with a single, elongated central nucleus; packs closely in sheet form.

Axon Terminal & Synaptic Cleft

dark brown part is the axon, wavy part is the synaptic cleft

Schwann Cell

Sarcolemma

clear outer membrane covering the fiber

Sarcoplasmic Reticulum (SR)

The lace-like/tubular blue netting wrapping each myofibril; forms enlarged sac ends called terminal cisternae that store calcium.

Transverse (T) Tubule

The vertical tubule running down between two cisternae; aka the blue part

triad

the three lines with the blue in the middle; One central T-tubule flanked by two terminal cisternae of the SR.

sarcomere

piriformis

the first arrow; largest one

Gemellus Superior

the second arrow

Obturator Internus

the third arrow

gemellus inferior

the fourth arrow

quadratus femorus

the fifth arrow

iliopsoas

combination of the psoa major (first arrow) and the iliacus (second arrow)

sartorius

1st arrow at the top; anterior view of the thigh/quad

rectus femoris

2nd arrow from the top

vastus medius

3rd arrow from the top

vastus lateralis

fourth arrow from top

vastus intermedius

Fibularis (Peroneus) longus

middle arrow

Fibularis (Peroneus) brevis

first and third arrows

superior rectus

directly above eye

inferior rectus

medial rectus

lateral rectus

superior oblique

inferior oblique

pectoralis minor

combination of three muscles

subclavius

right under the clavicle

Serratus anterior

trapezius

levator scapulae

rhomboid minor

1st line from the top

rhomboid major

2nd line from the top

supraspinatus

1st line at the top

infraspinatus

2nd line from the top

teres minor

3rd line from the top

subscapularis

deltoid

pectoralis major

left arrow

Latissimus dorsi

teres major

pronator teres

1st line at the top

flexor carpi radialis

2nd line from the top

palmaris longus

3rd line from the top

flexor carpi ulnaris

4th line from the top

brachioradialis

1st line at the top on the right

Extensor carpi radialis longus

2nd line from the top on the right

Extensor carpi radialis brevis

3rd line from the top on the right

Extensor digitorum

4th line from the top on the right

Extensor digiti minimi

3rd line from the top on the left

Extensor carpi ulnaris

2nd arrow from the top on the left

anconeus

1st arrow at the top on the left