3.6 Bones, Muscles & Joints of the Arms, Hands, Legs & Feet
Key Takeaways
- The carpus (wrist) contains eight small bones, the metacarpus (palm) has five, and the digits contain fourteen phalanges — twenty-seven bones in each hand.
- The humerus is the uppermost and largest arm bone; the ulna sits on the little-finger side of the forearm and the radius on the thumb side.
- Extensors straighten the wrist, hand and fingers, flexors bend them, abductors separate the fingers and adductors draw them together.
- The foot contains twenty-six bones — seven tarsals, five metatarsals and fourteen phalanges — and the tibia is the larger inner lower-leg bone while the fibula is the smaller outer one.
- Manicure and pedicure massage targets specific muscle groups, which is why identifying them supports both effective service and injury avoidance for the practitioner.
3.6 Bones, Muscles & Joints of the Arms, Hands, Legs & Feet
The NIC outline requires identification of muscles and joints and their functions related to the arms and hands and to the legs and feet. Because a cosmetology license in Washington includes manicuring and pedicuring, this material is service-relevant, not decorative.
Skeletal Vocabulary
Osteology is the study of bones. Bone is the hardest tissue in the body, composed of roughly one-third organic matter and two-thirds mineral matter. A joint is the connection between two or more bones; joints are either movable (elbow, knee, wrist, finger) or immovable (the sutures of the cranium). Tendons attach muscle to bone; ligaments connect bone to bone.
Bones of the Shoulder, Arm and Hand
| Bone | Location and note |
|---|---|
| Clavicle (collarbone) | Joins the sternum to the scapula |
| Scapula (shoulder blade) | Large, flat, triangular bone of the shoulder |
| Humerus | Uppermost and largest bone of the arm |
| Ulna | Inner and larger bone of the forearm, on the little-finger side |
| Radius | Smaller bone of the forearm, on the thumb side |
| Carpus (wrist) | A flexible joint of eight small irregular bones held together by ligaments |
| Metacarpus (palm) | Five long, slender bones |
| Phalanges (digits) | Fourteen bones — three in each finger, two in the thumb |
That totals twenty-seven bones in each hand. A useful mnemonic for forearm orientation: the radius is on the same side as the thumb, and rotating the palm is called radial rotation.
Muscles of the Shoulder, Arm and Hand
| Muscle | Function |
|---|---|
| Deltoid | Large triangular muscle covering the shoulder joint; lifts and turns the arm |
| Biceps | Muscle on the front of the upper arm; lifts the forearm and flexes the elbow |
| Triceps | Muscle covering the entire back of the upper arm; extends the forearm |
| Extensors | Straighten the wrist, hand and fingers |
| Flexors | Bend the wrist, draw the hand up and close the fingers toward the forearm |
| Pronator | Turns the hand inward, palm downward |
| Supinator | Turns the hand outward, palm upward |
| Abductors | Separate the fingers |
| Adductors | Draw the fingers together |
Memory hook: ab-ductors take the fingers away from each other; ad-ductors add them back together. Abductors and adductors are located at the base of each finger.
This group is also the practitioner’s own occupational risk map. Repetitive flexion and extension at the wrist while cutting, blow-drying or filing is precisely what loads the flexor and extensor tendons and compresses the median nerve inside the carpal tunnel. The neutral-wrist rule taught in ergonomics is a direct application of this anatomy.
Bones of the Leg, Ankle and Foot
| Bone | Location and note |
|---|---|
| Femur | Heavy, long bone of the thigh — the longest bone in the body |
| Patella | Kneecap |
| Tibia | Larger of the two lower-leg bones, on the inner (big-toe) side; the shin bone |
| Fibula | Smaller of the two lower-leg bones, on the outer (little-toe) side |
| Talus (ankle bone) | Forms the ankle joint with the tibia and fibula |
| Tarsals | Seven bones of the ankle region, including the talus and calcaneus (heel) |
| Metatarsals | Five long bones of the instep |
| Phalanges | Fourteen bones of the toes |
That totals twenty-six bones in each foot. Compare: twenty-seven in the hand, twenty-six in the foot.
Muscles of the Lower Leg and Foot
| Muscle | Function |
|---|---|
| Gastrocnemius | Attached to the lower rear surface of the heel; pulls the foot down (plantar flexion) |
| Soleus | Originates at the upper portion of the fibula; bends the foot down |
| Tibialis anterior | Covers the front of the shin; bends the foot upward and inward |
| Peroneus longus | Covers the outer side of the calf; inverts the foot and turns it outward |
| Peroneus brevis | Originates on the lower surface of the fibula; bends the foot down and out |
| Extensor digitorum longus | Bends the foot up and extends the toes |
| Flexor digitorum brevis | Moves the toes and helps maintain balance while walking and standing |
The gastrocnemius and soleus together form the calf and are the standard target of pedicure massage. The client who stands all day carries tension there, which is why a lower-leg massage is the most-remembered part of a spa pedicure.
Why This Matters at the Table
Manicure massage works the forearm and hand: effleurage along the forearm toward the elbow (insertion toward origin), joint movement at the wrist and each digit, and thumb friction across the metacarpals and the abductor and adductor groups at the base of the fingers.
Pedicure massage works the lower leg and foot: effleurage up the calf over the gastrocnemius and soleus, friction along the metatarsals, ankle rotation at the talus, and toe joint movement through the phalanges.
Contraindications are anatomical too. Do not massage over inflamed joints, varicose veins, an area of thrombosis, or any region where the client reports pain, and refer clients with diabetes or circulatory disorders to their physician before aggressive foot work — reduced sensation in the foot means the client cannot warn you that pressure or a tool is causing damage. This is also part of the reason Washington bans razor-edged callus removers outright under WAC 308-20-110(16).
How many bones are in the carpus, metacarpus and phalanges of one hand?
Which muscles separate the fingers, and where are they located?
Which lower-leg bone is the larger of the two, and on which side of the leg does it sit?