What muscles attach to the medial proximal tibia?

Muscles Attaching to the Medial Proximal Tibia

The primary muscles attaching to the medial proximal tibia include the sartorius, gracilis, and semitendinosus muscles, which collectively form the pes anserinus. 1, 2

Pes Anserinus Complex

• The pes anserinus consists of the conjoined tendons of the sartorius, gracilis, and semitendinosus muscles that insert on the medial aspect of the proximal tibia 1
• These tendons typically insert at the anteromedial aspect of the tibia and play a significant role in stabilization of the medial side of the knee joint 3
• In the standard anatomical arrangement, the semitendinosus and gracilis tendons attach superiorly and medially to the tendon of the sartorius muscle 2

Individual Muscle Attachments

Sartorius Muscle

• Originates from the anterior superior iliac spine and inserts onto the medial surface of the proximal tibia 4
• Crosses the anterior compartment of the thigh obliquely and descends towards the medial aspect of the knee 4
• Forms the most superficial layer of the pes anserinus insertion 2

Gracilis Muscle

• Inserts on the medial side of the tibial tuberosity as part of the pes anserinus 2
• Typically positioned between the sartorius (superficial) and semitendinosus (deep) tendons at the insertion site 1

Semitendinosus Muscle

• Attaches to the medial side of the tibial tuberosity, forming the deepest layer of the pes anserinus 2
• Works with the other pes anserinus muscles to provide dynamic medial knee stability 3

Anatomical Variations

• Anatomical variations in the arrangement of these tendons can occur, with potential clinical significance during surgical procedures in the knee region 2
• In rare cases, the sartorius muscle may have an accessory component originating from the inguinal ligament 4
• Variant patterns may include the sartorius tendon creating an additional superficial layer, with its proximal part lying just below the gracilis tendon and covering the semitendinosus tendon 2

Clinical Significance

• The pes anserinus provides dynamic stabilization to the medial aspect of the knee joint 3
• Pes anserinus syndrome (anserine bursitis) is a painful condition affecting this area 5
• The location of these muscle attachments is important during surgical procedures, especially anterior cruciate ligament reconstruction 2
• These muscles contribute to the "natural brace" for the knee joint and are important active stabilizers 6
• Weakness of these active stabilizers has been identified as a risk factor for incident symptomatic and progressive knee osteoarthritis 6

Biomechanical Importance

• The principal active stabilizers of the knee include these medial muscles, along with the quadriceps, hamstrings, and gastrocnemius muscles 6
• These muscles help control excessive hip adduction during running gait, which is a predictor of tibial bone stress injuries, particularly in female runners 7
• Strengthening these muscles is recommended to optimize lower extremity biomechanics and reduce the risk of knee injuries 7