Muscles and Joints: Location and Function

Elbow

• Flexion
• Extension
• Hyperextension
• Supination
• Pronation

Wrist

• Flexion
• Extension
• Hyperextension
• Abduction (left direction)
• Circumduction

Knee

• Flexion
• Slight rotation in flexion
• Extension

Ankle

• Flexion
• Extension
• Abduction
• Eversion
• Inversion

Keystone

(L) Between the neck and the manubrium. (F) Shrugging; works with other muscles to bring the head forward, backward, and to either side.

Sternocleidomastoid

(L) Front side of the neck. (F) Moves the head forward and rotates it; helps with inspiration; joins the skull to the clavicle and sternum.

Deltoid

(L) Upper arm. (F) Raises the arm to shoulder level and helps move it above the head.

Brachial Biceps

(L) Upper arm. (F) Flexes the arm and forearm; aids in wing attachment and detachment to the body's side.

Triceps Brachii

(L) Rear arm. (F) Extends the forearm.

Brachioradialis

(L) In the forearm; originates in the back of the humerus and ends in the radius, next to the wrist. (F) Assists in radial flexion.

Radial Forearm

(L) Over the radius, on the external face of the forearm. (F) Extends the hand.

Pectoralis Major

(L) On the chest, left and right of the sternum. (F) Moves the arm inward and is used in embracing.

Oblique Abdominal Muscle

(L) Side of the waist. (F) Bends the trunk to the sides, contributes to its rotation, and bends it forward.

Straight Crunch

(L) Between the chest and pubis. (F) Flexes the trunk forward.

Latissimus Dorsi

(L) Side and rear of the back. (F) Extension of the spine if both sides act together; assists in various arm movements.

Lumbosacral

(L) Through the spine to one side; this is composed of three bundles. (F) Collaborates in back extension and lateral bending.

Gluteus

(L) In the rear. (F) Works in all types of mobilizations of the pelvis; assists in lateral leg opening.

Quadriceps

(L) On the front of the leg, formed by four beams. (F) Knee extension; it is one of the strongest muscles of the body.

Hamstring

(L) A set of three muscles that originate in the ischium, descend behind the thigh, and end two in the tibia and one in the fibula. (F) Knee flexion and extension of the thigh.

Adductors

(L) Inner thigh. (F) Joining the thighs.

Anterior Tibial

(L) Next to the tibia at its external face. (F) Flexes the foot, lifts the inner edge of it.

Peroneal

(L) External surface of the fibula. (F) Extends and separates the foot.

Gastrocnemius

(L) Between the knee and ankle at the back. (F) Extends the foot.