Biol 252L Lab 5 Myology: Muscles of Head, Neck, and Upper Limb

What tissues make up a muscle?

1. Skeletal muscle tissue

2. Nervous tissue

3. Connective tissue

4. Blood vessels

Epimysium

Outermost layer of connective tissue on a muscle

Different arrangements of fascicles

1. Parallel - longer fascicles that are straight

2. Convergent - strong attachment on one side, narrow attachment on the other

3. Pennate (feather) - many more fascicles and cells to attach to a tendon

4. Circular - self-explanatory

Origin and insertion of a muscle

Origin is the more proximal/medial part

Insertion is the more mobile and distal attachment

Synergists vs antagonists

Synergists are muscles located at a similar location and attachments and have similar function

Antagonists are muscles that work opposite each other

Antagonist to biceps femoris

Rectus femoris

Synergist to biceps femoris

Semitendinosis

Tendon

The tough connective tissue on the ends of muscles

Platysma

Innervated by cranial nerve VII

Function: tenses neck and depresses the mandible (lowers the jaw)

Very large muscle going from neck down to shoulder

Frontalis

Innervated by cranial nerve VII

Function: raises eyebrow

Large muscle that spans the entire forehead

Orbicularis Oculi

Innervated by cranial nerve VII

Function: closes eyelid

Muscle that circles the entire eye

Zygomaticus Major

Innervated by cranial nerve VII

Function: raises corners of lips (smiles)

Diagonal looking muscle that connects from the corners of the mouth to the ears (thin-looking muscle)

Buccinator

Innervated by cranial nerve VII

Function: compresses cheeks

A little bit depressed, muscle that lies in the cheek area posterior to the mouth

Depressor Anguli Oris

Innervated by cranial nerve VII

Function: lowers corners of the lips (frown)

Muscle that is right on the face and connects from the corners of the mouth down to the chin area (on the side)

Occipitalis

Innervated by cranial nerve VII

Function: tenses scalp

Located on both sides of the back of the head (near occipital lobe)

Orbicularis Oris

Innervated by cranial nerve VII

Function: purses lips

Muscle located right around where the lips are (oris is oral is mouth)

Masseter

Innervated by trigeminal cranial nerve V

Function: closing the jaw (helps chew), elevates mandible

The muscle that is fan-shaped and is right where the cheek is

Temporalis

Innervated by trigeminal cranial nerve V

Function: helps close the jaw and masticate (chew), elevates mandible

Right where the temporal lobe would be it is a big flap on the side of the skull

Lateral Pterygoid

Innervated by trigeminal cranial nerve V

Function: protrudes (extend outward) the lower jaw (opens jaw)

Deeper than the medial pterygoid and is directly inside the coronoid process of the mandible

Medial pterygoid

Innervated by trigeminal cranial nerve V

Function: elevate jaw, move jaw medially

Located in front of the lateral pterygoid (like you can see it first) and it is right inside the mandible

Medial Rectus

Extraocular muscle (innervated by CN III, IV, and VI)

Function: turns eye medially

Its completely medial and it right by the nose bridge (for both eyes), goes straight back

Lateral Rectus

Extraocular muscle (innervated by CN III, IV, and VI)

Function: turns eye laterally

It is completely lateral and is on the outer horizontal part of both eyes (by the temples)

Superior Rectus

Extraocular muscle (innervated by CN III, IV, and VI)

Function: turns eye superiorly

Directly at the top part of each eye by the eye lid

Inferior Rectus

Extraocular muscle (innervated by CN III, IV, and VI)

Function: turns eye inferiorly

Located right at the bottom of each eye above the cheek

Superior Oblique

Extraocular muscle (innervated by CN III, IV, and VI)

Function: turns eye inferiorly and laterally (opposite to its name)

Starts at the back of the orbit and attaches to the eyeball on the medial superior side of each eyeball

Inferior Oblique

Extraocular muscle (innervated by CN III, IV, and VI)

Function: turns eye superiorly and laterally (opposite to its name)

A muscle that directly attaches to the eyeball and wraps around it on the inferior side (wraps around the inferior rectus)

Trapezius

Innervated by cranial nerve XI

Function: retract, elevate, and depress the scapula (shoulder bone), extend neck if used bilaterally

Large muscle that basically covers the entire back shoulder

Sternocleidomastoid

Innervated by cranial nerve XI

Function: turns head or flexes neck if used bilaterally

Thick muscle that comes from the back of the ear down to the clavicle

Extraocular Muscles

Deep muscle, innervated by CN III, IV, and VI

Function: positions the eyeball

All of the rectus muscles (located around the eye)

Suprahyoid Muscles

Deep muscle, innervated by CN5 (trigeminal) and CN VII (facial)

Function: elevate the hyoid bone and move the floor of the mouth (oral cavity)

Located between the mandible and the hyoid bone, basically directly posterior to the mandible on the bottom chin area

Pharyngeal Muscles

Deep muscle, innervated by CNX (vagus nerve)

Function: form the tubular wall of the pharynx (throat) (extend from the nasal cavities to the esophagus), swallowing

It is on the posterior part of where the throat would be located

Laryngeal Muscles

Deep muscle, innervated by CNX (vagus)

Function: important for speech, can open and close glottis during swallowing and coughing (moving vocal cords)

Located inferior to where the pharyngeal muscles were and are two small dots on the back of the glottis

Muscles of the Tongue

Deep muscle, innervated by CNXII (hypoglossal)

Function: move the tongue

Comprised of intrinsic (literally inside the tongue and controls shape) and extrinsic (outside the tongue and controls position) muscles

Located below and inside where the tongue is

Anterior Deltoid

Front-most third of the deltoid on the shoulder

Attaches distally to the humerus

Function: abduction of glenohumeral joint, flexion too

Middle Deltoid

Middle third of the deltoid on the shoulder

Function: abduction of glenohumeral joint

Posterior Deltoid

Back-most third of the deltoid on the shoulder

Function: abduction of glenohumeral joint, extension too

Pectoralis Major

Big superficial chest muscle, it is the breast

Function: adduct the glenohumeral joint (bring it back in)

Latissimus Dorsi

Lower back muscle that is basically directly inferior to the trapezius

Function: extends the humerus (bringing the arm back), adducts the glenohumeral joint (brings it back in)

Pectoralis Minor

Located deep to pectoralis major (underneath it)

Function: depresses the scapula

Serratus Anterior

Located on the lateral ends of the rib cage

Function: protraction of the scapula (moving arm laterally/anteriorly), can extend the reach of the arm

Levator Scapulae

Comes out of the scapula and moves superiorly and medially to connect to the neck area

Function: elevates the scapula

Rhomboids (Major & Minor)

Located directly medially to the scapula (minor is on top, major is inferior to it)

Function: retract the scapula (pulling it back in medially)

Coracobrachialis

Deep muscle

Function: adductor of the glenohumeral joint (brings it closer in)

Located on the anterior/medial side of the humerus, stretches from bicep area to shoulder

Teres Major

Function: extensor of the glenohumeral joint, internally rotates the joint

Deep muscle located just below the rotator cuff muscles, connects from inferior scapula to humerus

Supraspinatus

Function: abducts the glenohumeral joint (brings the arm out)

Most superior rotator cuff muscle (covers the supraspinous fossa)

Infraspinatus

Function: externally rotate glenohumeral joint

Largest rotator cuff muscle that stretches over the infraspinous fossa of the scapula

Teres Minor

Function: externally rotate glenohumeral joint

Superior to the teres major, also inferior to the infraspinatus (most inferior rotator cuff muscle on the posterior scapula)

Subscapularis

Covers the subscapular fossa of the scapula (anterior side of the bone)

Function: internally rotate the glenohumeral joint (it would pull the arm internally if we shrank the rubber band)

Brachialis

Function: flexion of the elbow (bicep curl)

Located posteriorly to the biceps brachii and is sandwiched between biceps and triceps brachii

*Brachium means upper arm

Biceps Brachii

Big bicep muscle in the anterior part of the upper arm

Function: flexion of the elbow joint (basically a bicep curl)

*Has two heads

Triceps Brachii

The tricep muscle, located in the posterior part of the upper arm

Function: extension of the elbow (it would pull the elbow joint apart, allowing for extension), all three heads combine to allow for this

How are the tricep heads arranged?

Three heads

1. Medial head - connected to humerus

2. Lateral head - connected to humerus

3. Long head - extends to the scapula (located beneath other muscle)

Anconeus

Triangular shaped muscle right below the elbow

Function: extension of the elbow

How can forearm muscles be divided (to learn best)?

1. Flexors of the wrist and digits (curling them) attach to medial epicondyle

   1. Anterior

2. Most extensors attach to lateral epicondyle

   1. (posterior)

Brachioradialis

Located along the forearm on the posterior side towards the radius (thumb)

Function: elbow flexor (*exception because it is on the posterior side and most posterior forearm muscles do extension)

Extensor Carpi Radialis Longus

Medial to the brachioradialis, longus means it is the longer one

Function: extend the radial (lateral) side of the wrist

*radial is lateral

THIS IS ON THE POSTERIOR SIDE OF THE FOREARM

Extensor Carpi Radialis Brevis

Medial to the brachioradialis, brevis means it is the shorter one

**THIS IS MEDIAL TO THE EXTENSOR CARPI RADIALIS LONGUS

Function: extend the radial (lateral) side of the wrist

*radial is lateral

THIS IS ON THE POSTERIOR SIDE OF THE FOREARM

Extensor Digitorum

Function: extends digits II-IV

Located medially on the posterior side to the extensor carpi radiali (thicker muscle)

Extensor Digiti Minimi

Function: extends digit V (digiti minimi literally means pinky and digit V)

Located medially to the extensor digitorum on the posterior side

Extensor Carpi Ulnaris

Located medially to the extensor digiti minimi on the posterior side (we are now on the pinky side)

Ulnaris - medial

Function: extends the ulnar (medial) side of the wrist

Supinator

Function: “unwinding”, it rotates the radius externally (supination)

It is literally wrapped on the radius bone on the proximal end

Abductor Pollicis Longus

Function: abduction (bringing it out) of digit I

Medial to the supinator (technically), it is wrapped around deep posterior part of the forearm and ends by going to the radius

Extensor Pollicis Brevis

Deep muscle

Function: extension of digit 1

Located medially to the abductor pollicis longus

Extensor Pollicis Longus

Deep muscle

Function: extension of digit I

Located medially to the extensor pollicis brevis (it is the longer of the two expensor pollicis muscles)

Extensor Indicis

Deep muscle, synergist with extensor digitorum

Function: extension of digit II

Located medially to the extensor pollicis longus (ends by extending out to digit II, index finger)

Flexor Digitorum Superficialis

Largest, flat muscle that is on the anterior side of the forearm, it is overlapped (covered) by the (it lies beneath them but is still superficial)

1. Pronator teres

2. Flexor carpi radialis

3. Palmaris longus

4. Flexor carpi ulnaris

Function: allows for flexion of the phalanges

Pronator Teres

Function: internally rotates the radius (protonation)

Most lateral out of the anterior side

It is on the radial side (hence its function)

Flexor carpi radialis

Very large muscle that is medial to the pronator teres on the anterior side

Function: flexes the radial (lateral) side of the wrist

Palmaris longus

Located medially to the flexor carpi radialis

Function: attaches to the palmar aponeurosis (connective tissue on the hand), flexes the wrist (tenses the aponeurosis)

Flexor Carpi Ulnaris

Located medially to the palmaris longus

Function: flexes the ulnar (medial) side of the wrist

Palmar aponeurosis

Thick connective tissue on the hand

Function: holds the skin of the palm in place

Pronator Quadratus

Deep muscle

Function: assists the pronator teres in the pronation of the hand

Located right on the wrist (most lateral muscle on the anterior side) posterior to the flexor pollicis longus and flexor digitorum profundus)

Flexor Pollicis Longus

Deep muscle

Lateral to the flexor digitorum profundus

Function: flexes digits I

Flexor Digitorum Profundus

Deep muscle

Medial to the flexor pollicis longus

Function: flexes digit II-V