Axial Skeletal Muscles

Muscles of the Head

The muscles of the head are responsible for facial expressions, mastication, and movements of the scalp and eyelids. Understanding their location and function is essential for identifying them on anatomical models.

• Orbicularis oris: Encircles the mouth; responsible for closing and puckering the lips.

• Orbicularis oculi: Surrounds the eye; enables closing of the eyelids.

• Temporalis: Located on the side of the skull above the ear; elevates and retracts the mandible.

• Epicranius frontal (frontalis): Forehead region; raises eyebrows and wrinkles forehead.

• Epicranius occipital (occipitalis): Back of the head; pulls scalp posteriorly.

• Masseter: Cheek area; primary muscle for jaw closure during chewing.

• Zygomaticus: Extends from cheekbone to corners of mouth; elevates corners of mouth (smiling).

Muscles of the Neck

Neck muscles facilitate head movement and support swallowing and speech.

• Sternocleidomastoid: Runs from sternum and clavicle to mastoid process; rotates and flexes the head.

• Sternohyoid: Located along the anterior neck; depresses the hyoid bone.

• Splenius capitis: Posterior neck; extends and rotates the head.

Torso Muscles

Torso muscles are involved in movements of the trunk, respiration, and stabilization of the body.

• Pectoralis major: Chest; adducts and flexes the arm.

• Serratus anterior: Lateral chest wall; protracts scapula.

• Trapezius: Upper back; elevates, retracts, and rotates scapula.

• Latissimus dorsi: Lower back; extends, adducts, and medially rotates arm.

• External oblique: Lateral abdomen; compresses abdomen, flexes and rotates trunk.

• Rectus abdominis: Anterior abdomen; flexes vertebral column, compresses abdomen.

Cat Muscle Dissection and Identification

Chest Muscle Dissection

These muscles are analogous to human chest muscles and are identified during cat dissection.

• Pectoralis major

• Pectoralis minor

• Serratus ventralis

Abdominal Muscle Dissection

• External oblique

• Internal oblique

• Transversus abdominis

• Rectus abdominis

Posterior Torso Muscle Dissection

• Latissimus dorsi

• Spinotrapezius

• Acromiotrapezius

• Clavotrapezius

• Spinodeltoid

• Clavodeltoid

Appendicular Skeletal Muscles

Pectoral Girdle Muscles

These muscles stabilize and move the shoulder joint.

• Deltoid: Covers shoulder; abducts arm.

• Pectoralis major: (see above)

• Teres major: Inferior to infraspinatus; adducts and medially rotates arm.

• Teres minor: Superior to teres major; laterally rotates arm.

Upper Arm Muscles

Responsible for flexion and extension of the forearm.

• Biceps brachii: Anterior upper arm; flexes elbow and supinates forearm.

• Triceps brachii: Posterior upper arm; extends elbow.

• Brachialis: Deep to biceps; flexes elbow.

Forearm Muscles (Arm Models)

Control movements of the wrist, hand, and fingers.

• Brachioradialis: Flexes forearm at elbow.

• Extensor carpi radialis longus: Extends and abducts wrist.

• Extensor digitorum: Extends fingers.

• Extensor carpi ulnaris: Extends and adducts wrist.

• Flexor carpi ulnaris: Flexes and adducts wrist.

• Palmaris longus: Flexes wrist.

• Flexor carpi radialis: Flexes and abducts wrist.

• Pronator teres: Pronates forearm.

Pelvic Girdle Muscles

These muscles move and stabilize the hip joint.

• Gluteus maximus: Extends and laterally rotates thigh.

• Gluteus medius: Abducts and medially rotates thigh.

• Tensor fasciae latae: Abducts thigh.

Upper Leg Muscles

Responsible for movement of the thigh and knee.

• Sartorius: Flexes, abducts, and laterally rotates thigh.

• Rectus femoris: Extends knee, flexes thigh.

• Vastus lateralis: Extends knee.

• Vastus medialis: Extends knee.

• Adductor longus: Adducts thigh.

• Gracilis: Adducts thigh, flexes leg.

• Adductor magnus: Adducts and medially rotates thigh.

• Biceps femoris: Flexes knee, extends thigh.

• Semitendinosus: Flexes knee, extends thigh.

• Semimembranosus: Flexes knee, extends thigh.

Lower Leg Muscles

Control movements of the ankle and foot.

• Gastrocnemius: Calf muscle; plantar flexes foot.

• Soleus: Deep to gastrocnemius; plantar flexes foot.

• Tibialis anterior: Dorsiflexes and inverts foot.

• Fibularis longus: Everts and plantar flexes foot.

• Extensor digitorum longus: Extends toes, dorsiflexes foot.

Cat Muscle Dissection and Identification (Appendicular Muscles)

Upper Arm Muscles

• Triceps brachii

• Biceps brachii

Forearm Muscles

• Brachioradialis

• Extensor carpi ulnaris

• Palmaris longus

• Flexor carpi ulnaris

Upper Leg Muscles

• Sartorius

• Gracilis

• Vastus lateralis

• Vastus medialis

• Semitendinosus

• Semimembranosus

• Adductor longus

• Biceps femoris

Lower Leg Muscles

• Gastrocnemius

• Soleus

• Tibialis anterior

• Extensor digitorum longus

• Fibularis longus

Summary Table: Major Skeletal Muscles and Their Functions

Additional info:

• Muscle identification is a key skill in anatomy and physiology, requiring knowledge of both location and function.

• Many muscles have analogous structures in humans and cats, which aids comparative anatomy studies.

• Muscle names often reflect their location, shape, or function (e.g., rectus means straight, oblique means angled).