Bony Landmark Thumb Spica: What Is It?

Thumb spica splints are devices used to immobilize the thumb and adjacent structures, particularly in cases of thumb metacarpal fracture, scaphoid fracture, lunate fracture, and thumb ulnar collateral ligament injuries. They are designed to decrease movement and provide support and comfort through stabilization of an injury. Thumb spica splinting has proven effective in treating bony and soft-tissue injuries of the lateral hand’s thumb, carpal, and metacarpal.

Bony landmarks of the hand include the proximal carpal bones (scaphoid, lunate, triquetrum, pisiform), distal carpal bones (trapezium, trapezoid, capitate, hamate), and the palpable bony landmarks on the palmar aspect of the wrist (fig. 1) such as the pisiform, scaphoid tuberosity, trapezial tuberosity, and volar radial. Common bone markings serve various anatomical, functional, and developmental roles, such as the radius on the side of the thumb and the ulna on the side of the pinky.

The base of the distal phalanx of thumb is the base of the median nerve, while the flexor Digitorum Profundis is the flexion of the wrist and fingers. The radial styloid, scaphoid tubercle, and Lister’s tubercle can be used as superficial landmarks for the first dorsal compartment.

To avoid shear force, ensure that the splint is moulded closely to the hand/arm and that the splint is moulded closely to the hand/arm. If a fracture is seen, refer to a fracture clinic, and if no fracture is found, consult a local medical office (LMO) to assess clinically.

What is a bony landmark?

Bony landmarks, also referred to as bone markings, are distinctive features observed in the bones of the skeleton, including the crest, fossa, process, and condyle. These features are crucial for identifying and recognizing the structural composition of the skeleton.

What is the bony landmark of the hand?

The carpal tunnel is a crucial part of the upper limb, with the flexor retinaculum forming the roof and floor of Guyon’s canal. The ulnar artery and nerve are contained within the flexor retinaculum. The flexor carpi radialis (FCR) tendon is located at the base of the second metacarpal and has a separate synovial sheath. The flexor carpi ulnaris (FCU) is located on the hook of the hamate and the base of the fifth metacarpal and does not have a tendon sheath.

The palmaris longus tendon is a thin, variable tendon that inserts on the transverse carpal ligament and the palmar aponeurosis and is absent in 20 of cases. These flexors play a crucial role in maintaining proper alignment and function in the upper limb.

Why is it called thumb spica?

The term “Spica” is used to describe a type of brace that uses small strips of Velcro to immobilize the thumb joint and restrict wrist joint motion. These braces typically encircle the thumb and wrist.

What position should the thumb be in for a thumb spica splint?

It is recommended that the thumb be maintained in a slightly flexed and abducted position, with the wrist extended to a range of 10-20°. The splint should permit unrestricted motion of the second through fourth metacarpophalangeal (MCP) joints, unless there is an additional injury.

What are the bony landmarks of the fingers?

Phalanges are long bones that form the finger and toe skeleton, consisting of proximal, middle, and distal phalanx. These bones serve as attachment points for ligaments and tendons, providing stability to the joints. They also have numerous muscular attachments that enable movement and flexibility of the fingers and toes. The flexor digitorum superficialis muscle attaches to the middle phalanges, allowing for finger flexion, while the extensor digitorum muscle attaches to the distal phalanges, allowing for finger extension. Interossei muscles, located between the metacarpals or metatarsals, attach to the proximal and middle phalanges, allowing for abduction and adduction of the fingers and toes.

Common injuries affecting the phalanges include fractures, dislocations, sprains, and tendon injuries. Fractures can occur at any point along the bone and can be displaced or nondisplaced. Dislocations occur when the bone is forced out of its normal position, often resulting in severe pain and swelling. Tendon injuries, such as mallet or trigger finger, can result from repetitive use or overuse, causing limited range of motion and discomfort.

What are the bones and bony landmarks of the knee?

The medial epicondyle, lateral epicondyle, tibial tubercle, fibular head, and inferior pole of the patella are commonly used landmarks in clinical settings. Previous studies have found that the distances from these landmarks to the knee joint line are 33. 9, 33. 4, and 12. 2 mm, respectively. However, this study chose to evaluate the most prominent point of medial epicondyle as it is more accurate and easier to locate in a surgical setting.

Several studies have evaluated these parameters with patients of different ethnicities, but the distances from landmarks in this study were comparable to most of these results, except for distances C and E. These distances could be explained by the evidence that both landmarks had high variability. Previous studies have reported that the fibular head and lower pole patellar are not a good reference to locate the knee joint line due to their variability in their position.

To overcome the weakness of distances from landmarks to the joint line, Servien et al. suggested converting these measured distances into a ratio of the femoral transepicondylar width (epicondylar ratio), which would be more reliable and have less variation. The standard deviation and range of C/FW (0. 05/0. 05–0. 3), D/FW (0. 04/0. 04–0. 3), and E/FW (0. 04/0. 05–0. 27) were still wider than other parameters.

Many studies supported our results that C/FW and E/FW had a high standard variation, independent of patient size, and concluded that fibular head and inferior pole patellar are not reliable landmarks to guide joint line level in revision TKA. Furthermore, the fibular head is difficult to access during surgery due to its location and thick soft tissue coverage.

The difference between our outcomes and previous research may be explained by variation in the ethnicity of participants, participant selection, measurement methodology, or observer differences.

These ratios can be effectively used in real operative settings. Intraoperatively, the surgeon can use a ruler or vernier calipers to measure FW from the patient’s distal femur, then multiply by the epicondylar ratio of the relevant bony landmark calculated in this study to get an accurate joint line distance from that landmark. For example, if a surgeon performing revision TKA in a male patient wants to know the joint line distance from the medial epicondyle, they can use the A/FW ratio calculated in this study (0. 35 in Table 3) multiplied by the patient’s FW, which gives distance A for the patient.

What are the three types of bone landmarks?

Bone markings are a crucial aspect of bone structure, indicating the presence of various functions and locations within the body. There are three main types of bone markings: articulations, projections, and holes. An articulation is a joint where two bone surfaces meet, conforming to one another to facilitate function. A projection is an area above the bone’s surface, serving as attachment points for tendons and ligaments. The size and shape of these markings indicate the forces exerted through the attachment.

A hole is an opening or groove that allows blood vessels and nerves to enter the bone, reflecting the size of the vessels and nerves that penetrate it. Bone cells and tissue are primarily composed of collagen fibers, which provide a surface for inorganic salt crystals to adhere. These salt crystals, formed when calcium phosphate and calcium carbonate combine to create hydroxyapatite, give bones their hardness and strength, while collagen fibers provide flexibility. Overall, bone markings play a significant role in bone function, location, and the penetration of blood vessels and nerves.

What is a spica cast on the thumb?

Thumb spica splints are devices utilized for the purpose of immobilizing the thumb and its surrounding structures.

What are the 5 bony landmarks that can be found near the elbow joint?

The elbow is a crucial part of the upper arm, where the humerus articulates with the ulna and radius, the forearm bones. It is home to three bony landmarks: the medial epicondyle, lateral epicondyle, and olecranon. The medial epicondyle is visible in frontal and rear views, while the lateral epicondyle is located in a dimple between the elbow and two muscles, the brachioradialis and the extensor carpi radialis longus. The olecranon, a large bony eminence of the ulna, is the starting point of the forearm and is the only mobile of the three. These landmarks are essential for understanding the anatomy of the elbow.

What bony landmark is the patella in?

The patella, the kneecap, is the largest bone in the body and is embedded in a sesamoid bone. It supports the quadriceps muscle, protects the knee joint, and supports various muscles, tendons, and ligaments. Common conditions and disorders that affect the patella include anterior knee pain, patellar dislocation, and patellar subluxation. Patellar dislocation is a partial dislocation where the bone is unstable in the joint but not completely displaced.

This can cause discomfort, unsteadiness, and a popping noise as the patella moves. Injuries or loose joint joints can also cause patellar subluxation. Common causes of knee pain include anterior knee pain or chondromalacia patella.

What are the three bony landmarks of the pelvis?

The pelvis is a complex structure consisting of three pelvic bones: the ilium, ischium, and pubis. The ilium is the largest of the three, while the ischium is the inferior posterior portion of the hip bone. The pubis, ischium, and ilium bones form the right and left hip bones, along with the midline sacrum and coccyx. The sacroiliac joints form the bony pelvis, a basin-shaped ring connecting the axial and appendicular skeleton.

The bony pelvis is crucial for various functions, such as a transitional zone for neurovascular structures, a junctional point between the spine and lower limb forces during locomotion, and a structure within which vital visceral structures like the female reproductive organs, urinary bladder, and rectum lie.

The pelvic brim is the line formed by the continuation of the pectineal line on the pubic bones, the arcuate line of the ilium, and the ala of the sacrum. The true pelvis is below this brim, while the false pelvis is part of the abdominal cavity.