The hand is made up of several groups of bones. There are 8 carpal bones arranged in two rows of four bones. These bones form the wrist and join the hand with the ends of the bones in the lower arm – the radius and the ulna. Moving away from the wrist towards the fingers are the metacarpal bones. These are the five long bones that form the palm of the hand. The metacarpals are attached to smaller bones, called the phalanges, which form the thumb and fingers. The fingers contain three phalanges and the thumb has two.

Joints between the bones in the hand, fingers and thumb allow movement and flexibility. The thumb is especially important because it enables us to grasp objects. Strong bands of tissue, called the collateral ligaments, support the wrist and connect it to the bones in the lower arm. The hand also contains tendons, or fibrous bands of tissue that attach muscle to bone.

There are two major nerves that feed the hand – the median and ulnar nerves. These nerves run down the arm and carry electrical impulses to and from the brain to control movement and sensation in the fingers, thumb, hand and wrist.

Thumb Problems in the New Mom

Some new moms complain of pain in the thumb, wrist, or forearm. The condition has been dubbed “mom’s thumb,” but is also known as de Quervain’s tendonitis or “baby wrist.” It occurs because women tend to cradle the head of the baby in the palms of their hands, extending the thumb to provide extra support for the head. The unusual repetitive positioning and weight of the baby put pressure on the tendons at the base of the thumb, causing irritation and inflammation. Women may complain of pain along the wrist that can radiate down the thumb or up the arm. Grasping or pinching with the affected hand increases the pain sensation. Some women develop a swelling on the base of the thumb. The symptoms may occur gradually or suddenly.

No one knows how many women are affected by “mom’s thumb.” The American Society for Hand Surgery says new moms are especially prone to the condition because they often use awkward hand positions to hold their baby. In addition, hormonal fluctuations during pregnancy can lead to irritation of the tendons.

Treating “Mom’s Thumb”

Traditional treatment for “mom’s thumb” is to immobilize the affected thumb and wrist by wearing a splint. Ice and oral anti-inflammatory medications may help reduce inflammation.

Ronald Adler, M.D., Ph.D., an Ultrasound Specialist at the Hospital for Special Surgery in New York City, says injections of cortisone may also be helpful. The patient is first given a local anesthetic. Then, using ultrasound for guidance, cortisone medication is injected into the tendon compartment. The anesthesia and injection help reduce pain and swelling. Some patients may need over-the-counter pain medications and ice for about a day until the cortisone starts taking effect. Many women have complete recovery after the injection. A small number experience relief for a few months and require a second injection later.

Research shows about 77 percent of women with “mom’s thumb” get relief with conservative treatments. When symptoms don’t go away or are severe, surgery may be recommended. The goal of the surgery is to enlarge the space in the tendon compartment to allow the inflamed tendon to move more easily.

For general information on “mom’s thumb”:

American Academy of Orthopaedic Surgeons

American Society for Surgery of the Hand