The Peroneus Brevis (also known as Fibularis Brevis) is a short muscle that lies at the lateral part of the lower leg deep to the Peroneus Longus. It is one of the three peroneus muscles (Pernoeus Longus, Peroneus Brevis and Peroneus Tertius). The Peroneus Brevis along with the Peroneus Longus are commonly injured during a lateral ankle sprain and the tendon of the Peroneus Brevis muscle is the most commonly dislocated tendon.
The Peroneus Brevis is innervated by the Superficial Peroneal nerve (L5-S2).
The Peroneus Brevis receives its arterial supply from the muscular branches of the peroneal artery.
The Peroneus Brevis is responsible for 63% of the power needed to evert the foot as well as assists in plantar flexion along with the Peroneus Longus. The peroneii muscle work together to provide dynamic lateral ankle stability during sudden ankle inversion stress.
Ankle and foot injuries are commonly seen in physiotherapy with a high prevalence of those injuries occuring at the lateral ankle. The most common injuries seen with the Peroneus Brevis is to the tendon by way of tendinopathy, dislocation/subluxation, sprain or splitting. Tendinous injuries to the Peroneus Brevis are usually caused by inversion or supination forces. With a lateral ankle sprain, it is possible that the Peroneus Brevis can tear and cause swelling at the lateral ankle. During a Supination-Adduction injury, the Peroneus Brevis tendon could be injured and could possible pull at the base of the 5th Metatarsal causing an avulsion fracture known as a Jones Fracture.
When assessing a patient for a Peroneus Brevis injury, an overall alignment of the leg and posture of the hindfoot must first be evaluated. Patients that present with hindfoot varus are predisposed to peroneal injury. Assessing the flexibility and correctability of the varus should be performed to determine the use of orthotic management.
Upon observation, peroneal disorders will often present with swelling just posterior to the fibula or along the lateral wall of the calcaneus. Patients typically present with posterolateral ankle pain that worsens with activity and improves with rest. Palpation may present with tenderness along the course of the tendons. Range of motion testing may show pain with resisted eversion, passive inversion stretch, or resisted plantar flexion of the first ray. Active circumduction of the ankle may re-create tendon subluxation. Special tests such as the peroneal compression test should be performed to assess pain, crepitus, and “popping” at the posterior edge of the distal fibula during forceful ankle eversion and dorsiflexion.
- Non-steroidal anti-inﬂammatory medication
- Activity modiﬁcation,
- Orthoses with lateral forefoot posting in mild cases
- For more difficult cases, immobilization in a short-leg cast or controlled ankle movement walker for six weeks may be helpful.
Open Synovectomy- The tendon sheath is opened longitudinally and any damaged area of tendon is debrided. Post-operatively, the foot and ankle are placed in a short-leg cast. Weight-bearing in the cast may begin after two weeks. Range of movement and strengthening are started after casting is discontinued at four to six weeks.
- Basit H, Eovaldi BJ, Siccardi MA. Anatomy, Bony Pelvis and Lower Limb, Foot Peroneus Brevis Muscle. InStatPearls [Internet] 2019 May 19. StatPearls Publishing.
- Lippert, Lynn S. Clinical Kinesiology and Anatomy. 5th ed. Philadelphia: F A Davis Company; 2016.
- Davda K, Malhotra K, O’Donnell P, Singh D, Cullen N. Peroneal tendon disorders. EFORT open reviews. 2017 Jun;2(6):281-92.
- Endurance Physio. Ankle Eversion (fibularis longus/brevis) Exercise. Available from:https://www.youtube.com/watch?v=JHyEHEwgc6A&feature=youtu.be [last accessed 13/02/2020]