Biceps brachii: origin, insertion, action and innervation
The biceps brachii has two heads arising from the scapula and inserts on the radial tuberosity. It flexes the elbow, supinates the forearm and is supplied by the musculocutaneous nerve.
Muscles of the human body
Origin, insertion, action and innervation of each muscle, explained clearly, with the 3D view from the app.
Upper limb
Brachioradialis: origin, insertion, action and innervation
The brachioradialis arises from the lateral supracondylar ridge of the humerus and inserts just above the styloid process of the radius. It flexes the elbow, most strongly in mid-pronation, and is supplied by the radial nerve.
Deltoid muscle: origin, insertion, action and innervation
The deltoid arises from the clavicle, acromion and spine of the scapula and inserts on the deltoid tuberosity of the humerus. It abducts the arm and is supplied by the axillary nerve.
Latissimus dorsi: origin, insertion, action and innervation
The latissimus dorsi arises from the lower thoracic spine, thoracolumbar fascia, iliac crest and lower ribs and inserts in the intertubercular groove of the humerus. It extends, adducts and medially rotates the arm.
Pectoralis major: origin, insertion, action and innervation
The pectoralis major arises from the clavicle, sternum and upper costal cartilages and inserts on the humerus. It adducts and medially rotates the arm and is supplied by the pectoral nerves.
Pectoralis minor: origin, insertion, action and innervation
The pectoralis minor arises from ribs 3–5 and inserts on the coracoid process of the scapula. It draws the scapula forward and downward, helps forced breathing and is supplied by the medial pectoral nerve.
Serratus anterior: origin, insertion, action and innervation
The serratus anterior arises from the outer surfaces of the upper eight ribs and inserts on the medial border of the scapula. It protracts and upwardly rotates the scapula and is supplied by the long thoracic nerve.
Supraspinatus: origin, insertion, action and innervation
The supraspinatus arises from the supraspinous fossa of the scapula and inserts on the greater tubercle of the humerus. It starts abduction of the arm, stabilises the shoulder and is supplied by the suprascapular nerve.
Trapezius: origin, insertion, action and innervation
The trapezius arises from the skull and the spines of C7–T12 and inserts on the clavicle, acromion and spine of the scapula. It elevates, retracts, depresses and rotates the scapula, and is supplied by the accessory nerve.
Triceps brachii: origin, insertion, action and innervation
The triceps brachii has three heads, from the scapula and the back of the humerus, and inserts on the olecranon of the ulna. It extends the elbow and is supplied by the radial nerve.
Lower limb
Biceps femoris: origin, insertion, action and innervation
The biceps femoris has a long head from the ischial tuberosity and a short head from the linea aspera of the femur, and inserts on the head of the fibula. It flexes the knee and the long head extends the hip.
Gastrocnemius: origin, insertion, action and innervation
The gastrocnemius has two heads from the femoral condyles and inserts on the calcaneus through the calcaneal (Achilles) tendon. It plantar flexes the ankle, flexes the knee and is supplied by the tibial nerve.
Gluteus maximus: origin, insertion, action and innervation
The gluteus maximus arises from the back of the ilium, sacrum, coccyx and sacrotuberous ligament and inserts on the iliotibial tract and gluteal tuberosity of the femur. It extends and laterally rotates the hip and is supplied by the inferior gluteal nerve.
Rectus femoris: origin, insertion, action and innervation
The rectus femoris arises from the anterior inferior iliac spine and above the acetabulum and inserts on the tibial tuberosity through the quadriceps tendon and patellar ligament. It extends the knee, flexes the hip and is supplied by the femoral nerve.
Sartorius: origin, insertion, action and innervation
The sartorius runs from the anterior superior iliac spine to the upper medial tibia. It flexes, abducts and laterally rotates the hip, flexes the knee and is supplied by the femoral nerve. It is the longest muscle in the body.
Soleus: origin, insertion, action and innervation
The soleus arises from the back of the fibula and the soleal line of the tibia and inserts on the calcaneus through the Achilles tendon. It plantar flexes the ankle and is supplied by the tibial nerve.
Tibialis anterior: origin, insertion, action and innervation
The tibialis anterior arises from the lateral condyle and upper lateral surface of the tibia and inserts on the medial cuneiform and first metatarsal. It dorsiflexes and inverts the foot and is supplied by the deep fibular nerve.
Trunk
External oblique: origin, insertion, action and innervation
The external abdominal oblique arises from the outer surfaces of ribs 5–12 and inserts on the linea alba, pubic tubercle and iliac crest. It flexes and rotates the trunk, compresses the abdomen and is supplied by T7–T12.
Rectus abdominis: origin, insertion, action and innervation
The rectus abdominis runs from the pubic crest and pubic symphysis to the xiphoid process and costal cartilages 5–7. It flexes the trunk and is supplied by the lower thoracic nerves (T7–T12).
Head and neck
Sternocleidomastoid: origin, insertion, action and innervation
The sternocleidomastoid arises from the manubrium of the sternum and the clavicle and inserts on the mastoid process. It turns the head to the opposite side, flexes the neck and is supplied by the accessory nerve.
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